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ABE

The general operating license is issued for series vehicles by the Federal Motor Transport Authority (KBA) if the vehicle complies with the current technical provisions of the Road Traffic Licensing Regulations (StVZO). The general type approval is national law and is only valid in Germany. It is gradually being replaced by European type approvals (ETG). The type approval expires if technical modifications are made to the vehicle, unless parts are used that have their own type approval or ETG and their correct installation has been checked by an approved expert from a testing organization. The result of the inspection must be entered in the vehicle documents. Anyone who drives a vehicle with an expired operating license on public roads is committing an administrative offence, which is punishable by a fine and points in Flensburg. Insurance cover also expires with the operating license. If the vehicle is listed in the ABE, the part can be fitted. Observe the conditions! For example, a technically permissible wheel/tyre combination may also require a speedometer adjustment or similar. The ABE states whether a modification approval is required for the part despite the ABE. Without such requirements, it is sufficient to carry the ABE.

ABG - General type approval

Is a test mark assigned by the KBA. This consists of a wavy line of three periods, one or two code letters, as well as a number and an additional symbol if required.

Air filter

Air filters are devices for separating aerosol particles from the air - i.e. suspended particles such as sand or dust, which can cause considerable wear in the engine. They are used in motor vehicles that have a petrol or diesel engine. On Simson mopeds and MZ motorcycles, different types of filters (mainly oil and dry filters) are installed depending on the model. Air filters are designed to transport a certain volume of air within a certain period of time. This is another reason why the air filters should not be removed without replacement and only filters with a similar intake volume to the original filters should be fitted when tuning. Air filters gradually become dirty during driving, which increases the resistance to the intake air - with the result that the fuel-air mixture changes, which negatively affects the running of the engine. Air filters should therefore be cleaned at regular intervals, but at least once a year.

Air filter cartridge

Air filter cartridges are installed in almost all mopeds, including Simson mopeds. They consist of a metal frame containing a coconut fiber mesh or foam as filter material, which is surrounded on both sides by an air-permeable metal mesh. The filter material is impregnated with oil. Air filters clean the intake air of so-called suspended particles such as dust and sand, as these could damage the engine. This happens because the suspended particles in the air flowing through the filter are bound by the oil-impregnated filter material. Air filters are designed in such a way that they always generate a certain intake pressure. However, the longer they are in use, the dirtier they become, which increases the resistance to the intake air and reduces the intake pressure, so that less air reaches the carburetor. This changes the composition of the air-fuel mixture and the engine runs more poorly. Air filter cartridges should therefore be cleaned or replaced regularly.

Alternator

In motor vehicles - and therefore also in motorized two-wheelers - an alternator is an electric generator that is driven by the combustion engine. In most two-wheelers, the alternator is coupled directly to the crankshaft to transmit power from the engine to the alternator. The alternator converts the mechanical energy (from the engine) into electrical energy, which is used to power the vehicle's electrical devices. The electrical power is approximately proportional to the mechanical power: the more mechanical energy is produced by the engine, the more electrical energy is generated. To ensure that the power supply is not interrupted even when the vehicle's engine is running slowly or at a standstill, motor vehicles are equipped with a battery that stores energy. The outdated-sounding term "alternator" can be explained by the history of vehicle construction, in the early days of which the electric generator had the sole function of supplying the vehicle's headlights with electricity. An alternative term for the alternator is "dynamo". Simson mopeds and MZ motorcycles also have alternators. These should be serviced together with the engine at regular intervals and after long breaks from riding (e.g. at the start of the season).

Ball flange

The ball flange is a component that is used together with the so-called calotte on Simson mopeds to retrofit the exhaust mounting. This is intended to solve a problem that occurs on many - especially older - Simson models. On these models, the exhaust is bolted rigidly to the engine - but only at two points. As the engine can move several centimeters in its rubber mounts while riding, the exhaust is subjected to strong vibrations that are not always synchronous, which loosens the mounting of the exhaust and generates noise. The spherical cap and ball flange ensure that the exhaust can move freely in all directions. The calotte is a metal ring a few centimeters wide that is placed on the exhaust, the ball flange is a narrow metal ring to which two spring elbows are attached, the other end of which is hooked into the cooling fins. The spring manifolds are wearing parts and should be replaced every few years.

Ball lamp

Bulbs with a round or spherical bulb are referred to as ball bulbs. They have a voltage rating of 6 V or 12 V and are primarily used as blinker lights in the Simson S51, S53 and S70 or as stop lights. Ball lamps can also be used for blinker or high beam control, as speedometer lights or for the idle indicator in many ETZ models. The voltage and wattage must always be adjusted in accordance with the vehicle's electrical system. It is just as important to check that they comply with the German Road Traffic Licensing Regulations (StVZO), as some bulbs, often colored versions, are not permitted in Germany or Europe. With an existing E-mark, however, Simson and MZ owners are on the safe side.

Base plate

The base plate is a component of the ignition system and the alternator on motorized two-wheelers. It is also installed in Simson mopeds and MZ motorcycles. It is a round metal plate on which a number of ignition system components are mounted: Two light coils (one each for the front headlight and for the rear and brake lights), the ignition coil and the battery charge. Depending on whether the motorized two-wheeler has a breaker ignition or an electronic ignition, there are further components on the base plate. In the case of a two-wheeler with contact breaker ignition, these are the contact breaker and the capacitor; in the case of a two-wheeler with electronic ignition, the so-called sensor coil. Above the base plate is the pole wheel, which is connected to the crankshaft via a disk spring (the so-called "e;crescent key "e;) and generates a magnetic field as soon as it is set in motion via the crankshaft - which in turn generates an electric current in the coils attached to the base plate. Base plates are largely maintenance-free, but the tight fit of all components attached to the base plate should be checked as part of regular maintenance of the ignition system.

Battery

The battery plays a rather subordinate role in most Simson and MZ models. As all models are equipped with a kick starter, it only has to supply power to the relevant consumers for the short time between switching on the ignition and starting the engine. Once the engine has started, the alternator or the charging coil takes over this function. The battery is only charged again when all consumers are switched on at the same time, as the output of the alternator/charging coil is then no longer sufficient in some cases. The battery then buffers the load peaks. Almost all models produced in the GDR can at least be ridden without a battery. The Simson motorcycles and also the AWO's can even be started. The MZ's have to be started without a battery. There is even an extra switch position on the ignition lock for this. Lead-acid batteries were generally used in the GDR. Lead was, and still is, an expensive raw material. With the Simson models S 50 N and S 51 N, the inventors showed that a moped could also run without a battery. A dry battery was only installed to support the horn.

Bellows

The bellows is a hose made of plastic, rubber or leather that is elastic and can be stretched or compressed like an accordion. Its function is to seal machine parts that mechanically slide into each other (and therefore "stretch" or "compress" in their overall length) and thus protect them from external influences and dirt. On older motorized two-wheelers - and therefore also on many MZ motorcycles and Simson mopeds - bellows are often found on the "e;motorcycle fork "e; the so-called front wheel suspension, where they protect the fork sealing rings located between the inner and outer fork tubes. On newer motorized two-wheelers, bellows are installed almost exclusively on off-road models and enduro bikes. Bellows are robust and not particularly susceptible to wear. However, they can be damaged by contact with sharp objects and should therefore be checked for leaks from time to time.

Bilux lamp

The Bilux lamp, originally a brand name from Osram, is a so-called two-filament bulb consisting of a dipped beam filament, shielding filament, main beam filament, glass bulb, guide disk, bulb base and connection contacts. They are used for high and low beam lighting, for example. The Bilux bulb is held by the reflector - a component of the headlight insert. Depending on the vehicle model, it has a voltage of 6 volts or 12 volts and optional wattages of 15 / 15 watts, 25 / 25 watts, 35 / 35 watts or 45 / 40 watts. Of course, the choice of the right socket also depends on the vehicle. ATTENTION: Some Bilux lamps are not valid in the area of the StVZO.

Blinker holder

A blinker bracket or holder is used as a motorcycle accessory to attach the indicators to the front and rear of the motorcycle. These are available for round or square indicators. The front blinker lights are mounted on the right and left side of the front fork bars using the corresponding blinker light brackets. The rear indicators are attached to the mudguard or to the seat bench screw connection with the appropriate screw connection. The diameter of the mostly galvanized or chrome-plated blinker brackets is between 10 - 15 mm. Chrome-plated accessories require regular care with special care products for chrome. Especially in winter, these accessories can be damaged (rust) by road salt or brine if they are not cared for properly.

Blocking tool

There are two main variants of locking tools for Simson and MZ. The gear locking tool is used, among other things, to open or fix the variator on Simson mopeds with a continuously variable automatic transmission. It is usually made of solid steel and has corresponding teeth that engage with the belt pulley teeth and thus prevent unwanted rotation. There are also blocking tools for the spark plug threads of two-stroke engines, also known as piston stoppers. This blocks the engine so that, for example, the nut on the crankshaft can be removed without hindrance. Of course, you can also make your own blocking tools. For safety reasons, however, you should refrain from such experiments and not take any risks, especially as the costs for a high-quality blocking tool in workshop quality are very limited.

Bougier tube

A bougie tube is a predominantly black tube made of robust plastic. On Simson and MZ two-wheelers, this tube is primarily used as a supporting element for the orderly routing of several cables. The bougie tube also has insulating properties and thus protects the cables from breakage or damage. They are available either by the meter or in various lengths. Depending on the number of cables and thickness, these practical insulating tubes are available with an internal diameter of approx. 4 mm to 10 mm. In order to be able to pull the cables out again easily and, above all, individually during repairs, the largest possible diameter should be preferred.

Brake caliper

The brake caliper is a component of the disc brake on motor vehicles, including motorized two-wheelers such as MZ motorcycles and Simson mopeds. Drum brakes, on the other hand, do not have a brake caliper due to their different design compared to disc brakes. With disc brakes, the brake calliper has the task of clamping the brake pads arranged on both sides of the brake disk, thereby slowing down the movement of the disk and finally bringing it to a standstill. With hydraulic brakes, the brake calliper is actuated by pistons, with mechanical brakes by pressing the corresponding hand or foot brake lever. The brake calliper is attached to the torque arm, which is fixed to the brake disk. Brake callipers are usually made of cast iron. Brake callipers on Simson mopeds and MZ motorcycles must be checked regularly as part of brake system maintenance. In doing so, it is particularly important to check whether both brake pads are evenly worn, as uneven wear is an indication that the brake pads are tensioned differently by the brake calliper.

Brake cam

The brake light switches on a two-wheeler are used to activate the brake lights. These are attached to the rear part of the two-wheeler and are activated when the two-wheeler rider presses the brake lever of the front brake or the brake pedal of the rear brake, so that the following traffic is made aware of the braking process. On two-wheelers, both the front and rear brakes are generally connected to the brake lights and both are equipped with a brake light switch. Due to the different design of the hand brake (lever) and the foot brake (pedal), in most cases the brake light switches for the front and rear brakes also differ in their design. On some Simson mopeds and MZ motorcycles, however, the brake light switches are suitable for both the front and rear brakes. In addition to these electromechanical brake light switches, there are also models that are actuated by the pressure build-up in the brake system itself. Brake light switches should be serviced regularly together with the brake system (at least every 5,000 kilometers) and replaced if necessary.

Brake fluid

Brake fluid is used in hydraulic brake systems to transfer power from the brake cylinder to the brake pads. As a rule, this fluid is based on glycol. Glycol is hydroscopic. This means that glycol is water-binding. Even in a closed brake system, the brake fluid gradually accumulates more and more water, making it increasingly dangerous for the motorcyclist. Above a certain water content in the brake fluid, the temperature of the brake pads will be high enough for the water content to evaporate, especially during hard braking maneuvers. This creates bubbles of water vapor, a gas. Unlike liquids, gases can be compressed very easily. The pressure that should actually act on the brake pads is lost in the compressed water vapor. The brake system significantly loses power and, in the worst case, becomes ineffective. Experts therefore recommend replacing the brake fluid annually, but at least every two years. ATTENTION: All work on the brake system should only be carried out by people who have the necessary specialist knowledge and appropriate tools! If in doubt, you should contact your trusted specialist workshop, at least for the brakes.

Brake lever

Brake levers are devices with which the brakes of motor vehicles - and therefore also motorized two-wheelers - are actuated. A distinction is made between hand brake levers and foot brake levers, also known as pedals. On motorized two-wheelers, both hand and foot brake levers are usually located on the right-hand side of the vehicle - the hand brake lever on the handlebars, the foot brake lever at pedal height. The (pulling) force is transmitted from the brake lever to the brake either mechanically or hydraulically. Mechanically, the force is transmitted via a wire cable that is encased in a flexible but pressure-resistant sheath (the so-called Bowden cable). Hydraulic brakes have two brake cylinders - the master cylinder on the brake lever and the slave cylinder on the brake. They are connected to each other by a pressure line. When the brake lever is actuated, pressure builds up in the master cylinder, which is transmitted to the slave cylinder via the pressure line. Depending on the model, Simson mopeds and MZ motorcycles are equipped with mechanical or hydraulic brakes. Brake levers should be regularly maintained and serviced, whereby it should be noted, particularly with mechanical brakes, that the wire cable wears out with prolonged use, which is noticeable in that the brake lever yields considerably even with slight pressure.

Brake light contact

On two-wheelers, brake light contacts are the components of the brake system that are used to establish a connection to the brake light. They cause the brake light to illuminate when the braking process begins and, conversely, to go out as soon as it ends. On Simson mopeds and MZ motorcycles, the brake light contacts are located on the brake light contact screw. On the one hand, the contact tongue and on the other, the notched nail are attached to it. While the contact tongue is used to connect the cable to the hub, the notched nail is the counterpart to the contact lug attached to the brake cam. The brake cam is used to operate the brake pads of the disc and drum brakes on two-wheelers, thereby initiating or ending the braking process. When braking, the brake cam is moved in such a way that the brake pad is pressed onto the brake disk or drum and at the same time the contact lug touches the notched pin. The brake light therefore illuminates as soon as the braking process begins. When the brake is released, the contact is interrupted again and the brake light goes out. Brake light contacts are comparatively delicate two-wheeled components that need to be replaced from time to time. If the brake light does not come on when braking, a defective brake light contact may be one of the possible causes.

Brake light switch

The brake light switches on a two-wheeler are used to activate the brake lights. These are attached to the rear part of the two-wheeler and are activated when the two-wheeler rider presses the brake lever of the front brake or the brake pedal of the rear brake, so that the following traffic is made aware of the braking process. On two-wheelers, both the front and rear brakes are generally connected to the brake lights and both are equipped with a brake light switch. Due to the different design of the hand brake (lever) and the foot brake (pedal), in most cases the brake light switches for the front and rear brakes also differ in their design. On some Simson mopeds and MZ motorcycles, however, the brake light switches are suitable for both the front and rear brakes. In addition to these electromechanical brake light switches, there are also models that are actuated by the pressure build-up in the brake system itself. Brake light switches should be serviced regularly together with the brake system (at least every 5,000 kilometers) and replaced if necessary.

Breaker

A circuit breaker (actually: breaker contact) is an electrical contact that opens and closes a circuit at regular intervals. Depending on their use, circuit breakers are designed in very different forms. They are also installed in motorized two-wheelers, including Simson mopeds and MZ motorcycles, where the breaker is located on the base plate and is an important component of the primary and magneto flywheel ignition. At ignition time, the breaker opens and interrupts the current flow of the primary coil, conducting the electrical energy to the ignition coil. This creates a high voltage, which leads to the generation of an ignition spark that ignites the compressed fuel mixture in the cylinder. The breaker is opened and closed by a slight bump on the pole wheel. Interrupters installed in motorized two-wheelers such as Simson mopeds and MZ motorcycles are wearing parts and must therefore be replaced regularly. Replacement is necessary if the specified distance between the contact plates can no longer be achieved when the breaker is open, even after readjustment.

Capacitor

A capacitor is a (passive) electrical component that serves as an AC resistance in an AC circuit. In simple terms, a capacitor consists of two surfaces that are electrically conductive (the electrodes), between which there is an insulating material (the dielectric). On motorized two-wheelers with breaker ignition, the capacitor is installed together with the breaker on the base plate. While the interrupter switches the ignition on at the optimum ignition time and then immediately switches it off again, the capacitor absorbs the current surge caused by self-induction (starting the engine without an external energy source) and stores its electrical energy so that it is withdrawn from the ignition contacts. The capacitor also prevents sparks from forming at the contact of the breaker. If the capacitor does not work properly, this leads to a loss of ignition coil energy, with the result that the ignition timing changes. Capacitors are also installed in MZ motorcycles and Simson mopeds. They are wearing parts and must be replaced regularly.

Carburetor

The carburetor of a Simson moped (e.g. BVF 16N1-11 for S 51 and S 70) is positioned on the cylinder by means of a carburetor flange connection. It ensures an optimum fuel-air mixture, i.e. it is responsible for the fuel supply and for fine distribution and atomization. As the cylinder can become very hot, there is a gasket on the flange to protect against air leakage and heat. The main components of the carburetor include the Venturi tube (air flow, at the narrowest point = vacuum generation), the jet needle (adjustable: higher = richer mixture, lower = leaner mixture), the needle jet or main jet (not adjustable), the idle jet or secondary jet (mixture preparation when idling), the slide (movable by throttle cable), the throttle cap (controls the air flow), the float (regulates the fuel supply) and the choke (starting aid by richer fuel mixture). The carburetor and all its components should be cleaned thoroughly, especially after the winter downtime. To do this, it should be disassembled into its individual parts and checked for signs of wear and tear, clogged jets and porous seals. The systematic replacement of defective parts can also replace major repairs in many cases. Only in the rarest of cases does the carburetor of MZ and Simson two-wheelers need to be completely replaced.

Carburetor sump

The carburetor bowl is also known as the float housing. Together with the float and the float needle valve, it serves as a supply and discharge element, for regulation and control. If there is no constant level in the sump or the housing is flooded, it is not uncommon for the float to be defective. The carburetor bowl is unscrewed before the repair. On some older Simson models from the early 70s, carburetor sumps that can be unscrewed from below were sometimes installed, which are somewhat easier to remove. When replacing or after cleaning the carburetor, make sure that the gasket is evenly fitted. This should also be replaced if necessary. It is also important that the carburetor bowl and gaskets are precisely matched to the respective carburetor, as a float bowl for the MZ ETZ 125 and 150, for example, will not fit the carburetor of a Simson Star SRA 25/50 under any circumstances.

CE marking

This is a marking affixed by the manufacturer at his own discretion which declares that the product he has put into circulation complies with the applicable requirements. The manufacturer is obliged to affix the CE marking to certain product groups.

Chain - Drive chain

A drive chain is the so-called traction element in a traction transmission - i.e. a transmission that is used to transfer torque from one shaft (or the gear wheel connected to it) to another. Unlike in a gear transmission, where the gears mesh directly with each other, in a traction transmission they are positioned at some distance from each other. This distance is bridged by the drive chain, which wraps around both sprockets and thus transmits the torque of the driven shaft to the non-driven shaft. Drive chains are also used on motorized two-wheelers such as MZ motorcycles and Simson mopeds. The advantages of drive chains include their comparatively low manufacturing costs and high efficiency. However, drive chains also require increased care and maintenance, whereby particular attention must be paid to sufficient lubrication and correct chain tension. With good care, the drive chain of a motorcycle or moped can last up to 30,000 kilometers, but if it is not cared for properly, it will be worn out after just a few thousand kilometers.

Chain alignment tester

As the name suggests, a chain alignment tester is used to check the chain or timing belt alignment on the MZ motorcycle or Simson moped by placing it on the sprocket. This test primarily serves to prevent signs of wear on the chain, chain wheel or sprocket, which can ultimately lead to a loss of power. Ideally, the tester is equipped with a dot laser. If the laser dot runs 100% along the chain plates after it has been applied, the rear wheel and sprocket are precisely installed on the axle. If not, they must be readjusted and retested. The check using the chain alignment tester only takes a few seconds and is characterized by an extra high level of accuracy in contrast to self-made systems.

Chain case

On Simson and MZ models, the rear part of the encapsulated drive chain guide is referred to as the chain case. The chain case, usually in two parts, encloses the chain sprocket on the wheel side and protects the chain from dirt and moisture. In the early Simson models, as well as in the first MZ models, the chain cases were made of injection-molded aluminium. On later models, they were made of black hard plastic. The chain case is part of the encapsulated chain guide on almost all Simson and MZ models. The chain runs from the engine-side chain sprocket through a chain tube into the chain case and back again. This protects the drive chain as far as possible from environmental influences and ensures a correspondingly long service life. In contrast to the Simsons, the chain case on the MZ fulfills an additional function. It also serves as a mount for the speedometer cable drive.

Chain tube - Chain protection tube

The two chain hoses connect the chain case with the motor housing and thus form an encapsulated system for the drive chain. The chain hose is made of rubber. A bellows at the end provides the necessary flexibility in length. This compensates for the ever-increasing distance between the motor housing and chain case when the chain is re-tensioned. The encapsulated guide protects the drive chain from dirt and moisture, which considerably extends its service life. However, the encapsulation often makes it tempting to neglect chain maintenance. Broken rollers are not visible. The condition of the chain can only be inspected after removing the engine housing cover. Particular attention should be paid to the bellows. With increasing age, the material becomes brittle and cracks appear. If moisture gets in there, it can no longer evaporate and collects in the chain case.

Charging system

The charging system is part of the electrical system of Simson mopeds. Together with the tail light choke, it forms a mechanical unit whose task is to charge the battery when the engine is running and to regulate the flow of electric current from the light coil to the tail light. The charging system and tail light choke prevent the tail light bulb from being destroyed ("burnt out") by overvoltage. They are necessary because the alternators installed in Simson mopeds have the characteristic of supplying an almost constant, speed-independent voltage only at nominal load ("full throttle"). To keep the voltage constant, the charging system contains a rectifier diode which converts the AC voltage supplied by the charging coil into DC voltage that can be stored by the battery. The tail light choke connected to the charging system is a coil that limits the current flow by increasing the AC resistance with increasing frequency (speed). The charging system should also be checked at regular intervals as part of vehicle maintenance. The check includes in detail The blocking effect of the rectifier diode, the charging current, the battery voltage at the charging system, the AC voltage upstream of the charging system and the voltage downstream of the charging system (without battery charging).

Choke

The choke is also known as the starter flap and serves as a starting aid. It is controlled by hand and provides a richer fuel mixture during starting or warm-up (fuel content is increased). For this purpose, the choke consists of another fuel nozzle, which is located at the outlet of the carburetor. The proportion of air sucked in is regulated by means of an air flap. In order to avoid excessive fuel consumption and sooting of the spark plugs, the choke should be withdrawn again after the warm-up phase. Older Simson models in particular, which still have an NKJ carburetor, are equipped with a (real) choke. However, the choke should not be confused with a starting carburetor, which is found on Simson mopeds with the BVF 16N1 and BVF 16N3 carburetor types or on MZ with BVF or Bing carburetors. In this case, the starting carburetor lever, which is usually located directly under the throttle grip, is used for starting. Colloquially, however, this variant is also referred to as a choke. If the choke has no or only an insufficient effect, thorough cleaning of the carburetor or the jets often helps. However, the optimum carburetor setting is often also a solution to the problem. Replacement is also possible and sometimes useful.

Clutch basket

The clutch basket is a component of motor vehicle clutches and is also installed on Simson mopeds and MZ motorcycles. Clutches are machine elements for connecting two shafts. The connection makes it possible to transfer the rotation (and thus the torque) of one shaft to the other - in the case of motor vehicles, from the crankshaft coming from the engine to the clutch shaft leading to the gearbox. More precisely, the torque is transmitted from the clutch basket connected to the crankshaft and via the clutch plates toothed with it to the clutch plates (friction linings), which in turn are connected to the clutch shaft. When the clutch is actuated (engaged), the clutch discs and plates are pressed together by a spring so that the force can be transmitted. When the clutch is disengaged (idling), the connection is released again. The clutch basket has recesses into which the teeth of the clutch disks - designed as gear wheels - engage. If replacement is necessary due to wear, the clutch basket and clutch discs should always be replaced together, as they have worn together after prolonged operation.

Clutch disk

The clutch plates (plates with friction linings on the outside and clutch plates on the inside) are arranged alternately according to the sandwich principle in the driving clutch basket. The connection with the clutch shaft is achieved by means of gearing. The entire disk pack is firmly pressed together by a pressure plate and, depending on the model, by one or more springs. This keeps the connection between the transmission and the engine closed. Only when the clutch lever is actuated does this connection open thanks to the pressure rod, as this relieves the spring pressure. Most Simson and MZ models have a multi-plate or multi-disc clutch. If the clutch is subjected to heavy loads or is incorrectly adjusted, the plates may overheat. These then often show a bluish discoloration and/or are distorted. If the clutch is "slipping", the contact pressure may be too low. In this case, you should not only replace the clutch plates, but also the springs.

Clutch gear

The clutch gear is part of the primary drive. It is located on the clutch basket and is connected to the drive pinion. The number of teeth depends on the design of the clutch gear. The Simson S51, S53, SR50 and KR51/2 models, for example, have 65 teeth and the S70, S83 and SR80 normally have 62 teeth. There are also clutch gears for centrifugal clutches, which are installed in the Duo4/1 and in the KR51/1S (Schwalbe). In the event of signs of wear, both components (clutch gear and drive pinion) should be replaced if possible for optimum coordination.

Clutch plate

Clutch plates are generally also referred to as clutch disks. The clutch pack, which is force-fitted by springs and pressure plate, is located in the so-called clutch basket. The inner plates, equipped with friction linings to increase the friction coefficients, are connected to the shaft so that they cannot rotate. The outer plates (intermediate plates), which on MZ and Simson are usually made of steel and are connected to the clutch basket by recesses, sit alternately in between. While the functional principle of multi-plate clutches (multi-plate clutch) is almost always comparable, there are differences in the number of plates depending on the model. The thickness of the plates is also decisive. If the clutch hardly separates or no longer separates at all, the clutch plates are often warped or stuck together. In this case, you could of course only replace individual plates. However, it would make more sense to replace all the inner and outer plates.

Clutch shaft

The clutch shaft in the ball bearing is part of the gearbox. The thrust washer and the gear wheels are located on it. The clutch pressure rods and the cylinder roller are located in the clutch shaft. The force of the clutch is transmitted to the clutch shaft so that it can work in harmony with the output shaft including the associated gearwheels and the shift fork (example Simson with M53 gearbox). (Simson S51, KR 51/2 = splined shaft with shift balls) When installing a new clutch shaft, ensure that it is secured with an appropriate circlip. For the Simson engines M541 and M741 (4-speed), for example, size 17 x 1.0 is required. You should also check that the previously removed ball bearing is undamaged.

Compression pressure gauge

As the name suggests, a compression pressure gauge (also known as a compression pressure tester) is used to determine the highest possible pressure of the piston in the cylinder. The measurement results in "bar" are displayed on a circular scale using a needle. Simson models should have a value between 8 and 10 bar. If the compression pressure is far below this, the cause could be seized piston rings or signs of wear on the cylinder. The most reliable results are obtained when the engine has already warmed up and the throttle valve is fully open. Compression pressure gauges are available either with a screw thread or with a rubber cone, which can then simply be pressed precisely into the spark plug opening. This tool is primarily required for restorations or for two-wheelers that have been out of service for a very long time and need to be made fit for re-registration.

Connecting rod

The connecting rod, often referred to as the connecting rod for short, connects the piston to the crankshaft. The interaction between the piston, connecting rod and crankshaft converts the linear up and down movement of the piston into the radial rotary movement of the crankshaft. The connecting rod is fitted with a connecting rod eye at the upper and lower end. The lower eye sits on the crankshaft crankpin, while the piston pin sits in the upper eye. There is no wear on the connecting rod itself, but the bearings in the connecting rod eyes wear out over time. The hobby mechanic is unlikely to have the necessary pressing tools to replace the connecting rod bearings. The only option here is to go to a specialist workshop. Nowadays, when overhauling, the steel-bronze plain bearings used in the past are usually replaced with modern and durable needle bearings.

Contact flag

The contact lug is attached to the brake cam, a component of the brake system of motorized two-wheelers. The brake cam is used to operate the brake pads and thereby initiate or end the braking process. When the brake is applied, the brake cam is also moved so that the brake lining is pressed onto the drum (in the case of a drum brake) or disc (in the case of a disc brake) and at the same time the contact lug touches the so-called notched nail. This is located on the brake light contact screw, to which the cable leading to the brake light is also attached, so that a connection to the brake light is established - which therefore lights up as soon as the contact lug hits the core nail. The tight fit of the contact lug on the brake cam should be checked on Simson mopeds and MZ motorcycles as part of the brake system inspection.

Control section

he control unit is part of an electronic ignition system. It adjusts the ignition timing to the engine speed. A certain amount of time elapses between the ignition pulse being triggered at the ignition coil and the actual spark at the spark plug. It is therefore necessary to interrupt the charging current of the ignition coil (ignition pulse) slightly earlier than the ignition spark should ignite the gasoline-air mixture in the combustion chamber. This causes the following problem. The time delay of the ignition coil is due to the design and is always the same. However, the engine speed changes. As a result, the ignition timing "wanders" with conventional contact breaker ignition systems. The higher the engine speed, the later the ignition takes place. Above a certain speed, combustion is no longer optimal and the engine produces less power. With electronic ignition systems, the control unit ensures that the ignition timing follows the engine speed and is always ignited at the optimum time over the entire speed range.

Cylinder

The cylinder is a cylindrical chamber (working chamber) in which the piston movements take place. The lower end is in the crankcase and the cylinder head (cylinder cover) is at the top. Simson used cast iron with lamellar graphite (relatively low expansion under high temperatures) for production. The slots machined into the cylinder liner (optionally two or four channels) serve as exhaust and intake (mixture feed into the combustion chamber - exhaust gases from the combustion chamber) as well as transfer ports. The cylinder is cooled in the shrink-wrapped aluminum heat sink by means of a fan on older motorcycles or by the airflow. Apart from the BK 350 with a two-cylinder boxer engine, various prototypes, sports versions or custom conversions, Simson and MZ mopeds and motorcycles usually only have one cylinder. The calculation of the cubic capacity in cm³ is made up of the piston stroke and the diameter of the cylinder liner. Cylinders are wearing parts. If the cylinder is to be honed (fine bore and honing), special expertise and above all special tools are at the top of the list of requirements. If a replacement is necessary in the case of uncorrectable defects, it is advisable to replace the cylinder including the head, piston, cylinder studs and piston rings. However, cylinders without cylinder liners and pistons are also available. As always, tuning cylinders must comply with StVO regulations.

Cylinder head

In single-cylinder two-stroke engines, the cylinder head is not a complicated component. It forms the upper part of the combustion chamber and essentially consists of a cast part with cooling fins, four holes for the tie rods and a threaded hole for the spark plug. In four-stroke engines, on the other hand, the valves and their drive are housed in the cylinder head. The intake and exhaust ports also run through the cylinder head in four-stroke engines. Although the designation is the same, two-stroke engines are more of a "simple cover", while four-stroke engines are a complex component with many components.

Cylindrical roller

Cylindrical rollers are rolling elements - i.e. rotational elements made of a hard material (such as steel) which, as elements of a linear roller guide or a rolling bearing, reduce the friction arising between the various components of the bearing or guide. Rolling bearings are bearings in which rolling bodies (such as cylindrical rollers) located between an inner and an outer ring reduce the frictional resistance - and thus assume the function of lubrication in so-called plain bearings. Rolling bearings are used for shafts and axles. Linear rolling guides, on the other hand, are used for the friction-free translation (displacement) of one or more machine assemblies while maintaining the (linear) direction of movement. In roller bearings and some linear roller guides, the individual rolling elements - such as cylindrical rollers - are always kept at the same distance from each other by a so-called cage. Cylindrical rollers are also used in Simson mopeds and MZ motorcycles, including in the crankshaft and in the rocker arm bearing.

Damping insert

The muffler insert is a component in the exhaust systems of two-wheelers. The muffler insert is pushed into the end piece of the moped's exhaust system and is used to reduce the so-called muzzle noise that occurs when the exhaust gases leave the exhaust system. Muffler inserts for Simson mopeds have been developed in different versions. In addition to the standard model, a double-pipe muffler insert was also produced (which was installed ex works in the Simson Sperber SR4-3, for example) as well as a special muffler insert for the so-called pointed cone end piece. This is functionally identical to other end pieces, but has a shape reminiscent of the end piece of a cigar, i.e. it is pointed. The pointed end piece and the corresponding damping insert were used in the models of the Simson bird series - Simson KR51/1 "Schwalbe", KR51/2 "Schwalbe", SR4-2 "Star", SR4-3 "Sperber" and the SR4-4 "Habicht". As part of the care and maintenance of the exhaust system, the muffler insert is pulled out and should be freed from the carbon deposits that build up on it during prolonged use by burning or brushing it off.

DEKRA - DEKRA - German Motor Vehicle Inspection Association

DEKRA is a group that emerged from an inspection company founded in 1925 and focuses on the inspection of motor vehicles and technical systems.

Disc spring

The disc spring actually gets its name from its visual resemblance to a deep plate. The spring force results from the material compression in the inner area. The decisive advantage of diaphragm springs is their low height compared to their diameter. This makes diaphragm springs particularly suitable as clutch springs for two-wheelers. The diaphragm spring presses the clutch plates together and thus creates the frictional connection between the crankshaft and gearbox. When the spring is released when the clutch lever is operated, the clutch disengages. On MZ and AWO sidecars, diaphragm springs are also used on the steering head to dampen vibrations.

Distance gauge

In terms of function and use, distance gauges are comparable to feeler gauges and are therefore usually mentioned in the same breath. >> see term feeler gauge << However, the term precision valve gauge is also commonly used for this measuring device during maintenance work on Simson mopeds or MZ two-wheelers. The conical blades (either individually with 0.4 mm, in a set of twelve from 0.05 mm to 0.6 mm or in a set of twenty from 0.05 mm to 1 mm) are usually made of hardened spring steel and are therefore somewhat more robust. Nevertheless, you should not do without a protective cover or storage in a tool bag and should handle them as carefully as possible.

EC/ECE type approval

Basically like an ABE. However, the area of validity refers to all member states of the European Community and other participating countries. The part is then marked with an 'E' test mark, the number behind it is the country code. Simply install and carry the documents (if enclosed).

ELBA

The abbreviation ELBA stands for "Elektronische Lade- und Blinkanlage", a technical innovation that was installed in Simson mopeds from the mid-1980s. The ELBA replaced the traditional charging system on Simson mopeds and added an electronic flasher unit. A special feature of the ELBA compared to the batteries used until then is that the charging current is regulated depending on the charge level of the vehicle battery. When the battery is fully charged, the charging current is automatically switched off in the ELBA so that the battery can no longer be overcharged. The automatic cut-off takes place via a so-called thyristor. This is an electrical component that switches off when the current falls below a certain minimum current (the holding current) and thus becomes non-conductive. The ELBA was first used in 1986 on the Simson SR50/80, the successor model to the legendary Simson "Schwalbe". This first version was still an ELBA with 6 volts (V). From 1988, ELBAs with 12 V were installed in all newer Simson models.

Engine mounts

The engine mount is a component that dampens vibrations on two-wheelers from the East German manufacturers MZ and Simson (but also on all other motor vehicles). These vibrations are caused by bumps in the road and contact with obstacles (such as when the wheel hits a kerb) and are transmitted from the chassis via the frame to the engine. Technically speaking, bearings enable movements in certain desired degrees of freedom and prevent them in certain undesired degrees of freedom. Engine mounts for Simson and MZ are usually made of metal and rubber. Modern hydromounts - i.e. mounting elements equipped with hydraulic damping - have not yet been installed on them. Engine mounts are functionally exposed to the effects of strong mechanical forces during the entire ride. They are therefore one of the wearing parts of every motorized two-wheeler and should be checked not only as part of routine maintenance but also whenever there are noticeably strong vibrations coming from the engine.

Entry

Registration is not an official term. The correct term is modification acceptance and is carried out with the aid of an ABE or a TG. A correction of the vehicle documents takes place at the 'next opportunity' but may also be necessary immediately (e.g. in the case of a change in performance). In the new federal states, only the DEKRA is allowed to make registrations, in the old federal states only the TÜV is allowed to do this.

Exhaust

Exhaust is the term for the exhaust system of an internal combustion engine installed in a motor vehicle. In addition to discharging the exhaust gases, the exhaust also fulfills another important function - it dampens the pressure surges generated during combustion and thus reduces the noise emissions of the two-wheeler. When caring for and maintaining exhaust systems for two-wheelers, particular attention must be paid to the tight fit of the exhaust and the components attached to it (especially the heat shield). Due to their exposed position, the exhaust systems of two-wheelers can be damaged more easily than those of other motor vehicles. In addition, two-wheeler exhausts - also for Simson and MZ - are often chrome-plated. Chrome is a material that is susceptible to weathering, which means that chrome-plated components can be damaged more easily during continuous operation of the two-wheeler than non-chrome-plated parts, especially through contact with road salt in winter. To prevent corrosion, chrome-plated two-wheeler exhausts should therefore be cleaned regularly with special chrome care products.

Exploded view

An exploded view is a type of graphic representation in which a complex object consisting of several individual parts is depicted in such a way that the individual parts are spatially separated from each other - so that they appear to fly apart in the event of an explosion. Exploded views are used for motorized two-wheelers, especially for engines. This type of representation has the advantage that the position of the individual components of the engine in relation to each other and thus their interaction is illustrated. If exploded drawings are used in spare parts catalogs, the individual assemblies and components are often provided with order numbers. This has the advantage for the customer that he can immediately identify a defective part even without knowing the correct technical term and order the appropriate spare part. Exploded views are also frequently used in assembly instructions, as they can be used to explain the individual steps of assembly or disassembly particularly well. Exploded views were used by both Simson and MZ and can be found in (historical) spare parts catalogs or can be ordered as wall posters.

Feeler gauge

As the feeler gauge can be pulled apart like a fan, it is often referred to as a fan gauge. This measuring tool can be used to determine exact gap dimensions. The so-called feelers (flat metal blades), which can be inserted into the gap to be measured, therefore have different thicknesses and are of course marked accordingly. Guide gauges with nine blades and measuring ranges from 0.04 to 0.08 mm with 0.01 mm accuracy or 0.1 to 0.3 mm in measuring increments of 0.1 mm are common for Simson. Alternatively, there is also a version with 20 blades from 0.05 mm to 1 mm in 0.1 mm increments. Guide gauges (see also distance gauge) are indispensable for setting the breaker contact distances and the spark plug, among other things. They can also be used to check the valve clearance. As the feelers are often very sensitive and can therefore bend, you should be very careful when measuring.

Fixed wheel

The term fixed gear is used in transmission technology. For each gear in a sequential gearbox, several pairs of gears are responsible for power transmission between the input shaft and the output shaft. The term fixed gear always refers to the gear that is permanently connected to the corresponding shaft. Its counterpart, the idler gear, is pushed into the desired position by the shift claw, so it is not friction-locked to the shift shaft, but can be moved on the axle. Each gear has at least one fixed gear and one idler gear on the corresponding shafts. The whole story becomes complicated when the idler gear sits on its own shaft as a fixed gear. When ordering, you should therefore always pay close attention to the gearing and the exact order numbers. Depending on the angle of view, the idler gear of a gear can also be a fixed gear on its own shaft.

Flange gasket

The flange gasket is located between the carburetor and the intake flange on the cylinder. (On four-stroke engines on the cylinder head). Its primary task is to seal the intake tract. On older models in particular, it is also intended to insulate the carburetor from the high engine temperature. This is where the term insulating flange comes from. If the flange gasket is worn, the engine draws in secondary air. The mixture becomes too lean and the engine overheats. So if the spark plug image is clearly too bright, you should spray brake cleaner or starting aid spray onto the intake duct while the engine is running. If the engine revs higher, it is drawing in secondary air. Be careful with throttled motorcycles! Here, a different flange gasket with a smaller passage is part of the throttle kit. Replacing it with the original part could result in driving license problems.

Flasher unit

The flasher unit is responsible for automatically switching the lights on and off. These components are most frequently used in the direction indicator to switch blinker lights. If the flasher unit should become defective, the spare part must be replaced - on Simson MZ, it is installed in the flasher relay in the engine compartment of the vehicle. When replacing the flasher unit, the number of connections must be taken into account. indicator units are now available with both two and three connections . You should also check whether the replacement parts are compatible with LED or conventional bulbs. Flasher units are available in 6V and 12V versions. The 6V flasher units are suitable for the Schwalbe, Sperber and Habicht models, while for the Simson S51 and S70 as well as MZ ETZ 125 to 250, it is better to use a 12 volt flasher unit. You can also recognize a high-quality flasher unit by the fact that it is fitted with foam rubber. This serves as a buffer and ensures stability.

Float

The float with its two float chambers is one of the components of the carburetor and is responsible for regulating the fuel supply and ensuring a constant level in the carburetor sump. The fuel first takes the route from the tank through the fuel hose, then flows into the carburetor, then passes through the open float needle valve and enters the sump. The float itself lies (floats) on top and ensures that the valve closes in good time when the optimum amount of fuel is reached. A functioning float thus prevents the water level from becoming too high and flooding. Although Simson floats are generally very robust, cracks can still occur in the float chambers. In this case, the component loses its buoyancy, submerges and no longer closes the valve. A defective float valve needle is also often responsible for starting problems. If the float has to be replaced, you should pay attention to the exact height. With the BVF 15N1-5 carburetor, it is 28 mm when closed and 32 mm when open. A Simson with BVF 16N1-12 requires a closed height of 29 mm and an open height of 33.5 mm. The position of the generally very sensitive float needle, on the other hand, can be optimized, although changing the position of the needle in the plate requires a high degree of dexterity and a little specialist knowledge.

Fork oil

It is like transmission sand, only more fluid in terms of aggregate level. Fork oil is a hydraulic oil that is used for the vibration damping function of a telescopic fork. The fork oil flows through the holes in the damper piston, slowing down the movement of the dip tube and stanchion and thus preventing the suspension from bouncing. The damping properties of the fork can be influenced by using different viscosities. The smaller the viscosity number, the thinner the oil and the softer the damping. Oil works depending on the temperature. In the winter months, we therefore recommend using the thinnest possible oil, otherwise the fork will become too hard at sub-zero temperatures. At the height of summer, however, the same oil can be too soft for sporty riders, resulting in spongy front wheel damping. When changing the fork oil, pay very close attention to the prescribed quantity. In general, the fork oil is always changed in both fork legs at the same time.

Four-stroke engine

Four-stroke engines are internal combustion engines that are used in motor vehicles, including MZ motorcycles and Simson mopeds. Put simply, four-stroke engines compress the fuel-air mixture and then burn it, with the combustion process being triggered by spark ignition (using the spark plug). A characteristic feature of four-stroke engines is that they have intake and exhaust valves, which regulate the flow of the unburned fuel-air mixture and the escape of exhaust gases and enable precise timing of the work processes. A characteristic feature of the four-stroke engine is that one working cycle consists of four piston strokes, with each piston stroke corresponding to one working stroke: intake (1st stroke), compression (2nd stroke), working (3rd stroke) and exhaust (4th stroke). The advantages of the four-stroke engine include the relatively low fuel consumption due to the more precise timing and its higher torque. In motorized two-wheelers, four-stroke engines are almost exclusively installed in larger machines with a displacement of approx. 500 cm³ or more, including numerous MZ motorcycles.

Frame - frame beam

The usually powder-coated frame beam protects the engine and other components on the one hand and stabilizes the entire frame construction on the other. In many cases, the lower beams are already welded to the footrest supports. On the Simson Enduro S51E, the frame beam is standard and is simply referred to as the Enduro struts. Opinions differ in the biker scene when it comes to appearance, but in terms of practicality, these struts make perfect sense. If you want to build your own frame downtube, you should definitely think about the brackets, i.e. the approx. 4 mm thick weld-on brackets or the gusset plate (e.g. for S50, S51 and S70) for fastening. There are also custom-fit covers for the downrights for Simson models.

Fuel hose

The fuel hose connects the fuel tank and carburetor on motorized two-wheelers. Both the fuel tank (more precisely, the fuel tap) and the carburetor have hose nozzles to which the fuel hose can be connected. The outer diameter of the hose nozzle - which varies depending on the vehicle type - determines how large the inner diameter of the fuel hose may be. Petrol hoses for motorized two-wheelers are made of different plastics. A flawless fuel hose is essential to prevent the engine from "stuttering". Most Simson mopeds and MZ motorcycles have an integrated fuel filter on the fuel tap (i.e. at the outlet of the fuel tank) to filter the smallest particles out of the fuel before they can reach the engine. Additional filters can also be inserted into the fuel hose. However, it should be noted that on some models (e.g. the Simson Schwalbe) the gradient between the fuel tank and carburetor is very small, so that the installation of additional filters can impede the fuel flow. The fuel hose of Simson mopeds and MZ motorcycles should be checked at regular intervals for leaks and a tight connection to the hose nozzle.

Full acceptance

Takes place when the vehicle registration document for a vehicle has expired. A full inspection must also be carried out if vehicles have been imported into Germany from abroad. This also applies to mopeds if they were not previously registered in the territory of the former GDR!

Gear oil

As the pistons and cylinders of two-stroke engines are lubricated via the mixture, a suitable gear oil can be used in the gearbox to lubricate the gears, bearings and mechanical seals accordingly. GL80W or GL-3 gear oil is recommended for Simson and MZ engines. According to the operating instructions, the gear oil must be changed every 8000 km. If you ride less, you should change the oil annually or at least every two years.

Gearbox

The gearbox is a machine element that changes motion variables. Because of this function, the gearbox is also referred to as a converter element. The gearbox is usually positioned between the (driving) engine and a (driven) working machine or - as in the case of motorized two-wheelers - a machine part. Two-wheel gearboxes are connected to both the engine and the machine part with a clutch. There are several types of gearboxes, whereby gearboxes that consist exclusively of fixed components are referred to as mechanical gearboxes. Mechanical gearboxes are further classified according to the type of power transmission. Gearboxes with gears are particularly widespread. They were also installed in most Simson and MZ two-wheelers. In gear transmissions, torque is transmitted by the gears of the transmission moving together with the shafts and axles on which they are mounted or supported. The distance between two gears is always dimensioned so that their teeth can mesh in order to transmit the rotary motion from one gear to the other. The speed can be changed by varying the size of the gears, thereby increasing or decreasing the torque. Gears on Simson and MZ two-wheelers are lubricated with gear oil and should be serviced regularly.

Glass base lamp

Glass base lamps are better known as glass squeeze base lamps or wedge base lamps. They are particularly economical and incorporating the socket into the molded plastic housing is quite straightforward. In the example W2.1×9.5d, the glass squeeze base thickness is 2.1 mm, the width is 9.5 mm and the number of contacts is two. In motorcycles from MZ (e.g. MZ 500 R) or motorized two-wheelers from Simson, these types of lamps are occasionally used as control or instrument lighting because they have been additionally installed or replaced. Lamps with glass bases are usually very inexpensive, but often do not last very long. The StVO also requires an E-mark for use on public roads.

GS - tested safety

Is a voluntary marking applied by the manufacturer to products that are not subject to CE marking requirements. Product testing is carried out by an independent testing or certification body and is regulated by law.

Guide pin

The guide pin is a conically shaped special tool. It makes it easier to fit the piston pin in the piston. To do this, the previously oiled piston pin is placed on the guide pin and then inserted into the needle bearing. For pistons with shims, we recommend using a guide pin with a press-in tip. Always pay attention to the model-dependent length and diameter dimensions. An appropriate ejection device is suitable for ejecting the pin. Without special tools (guide pin and blocking tool), the dreaded "e;piston seizure "e; could quickly occur after cylinder or piston replacement due to inaccurate piston rings. The investment in this absolutely affordable auxiliary tool is therefore worthwhile for Simson and MZ owners in any case.

H4

he H4 is a 12-volt twin filament halogen lamp with two tungsten filaments, one filament being responsible for the high beam with 60 watts and the other filament for the low beam with 55 watts. The first presentation of the H4 was back in 1966 and it was actually used for the first time in 1971. The elongated glass bulb is filled with a special halogen protective gas, including bromine and iodine additives. To avoid glare, the diffusing lenses for the H4 are often asymmetrically ribbed, and there are also H4 lamps with a higher light output (100 / 90 watts) for Simson and MZ. However, these are not permitted in the area of the StVO. Care must also be taken when converting MZ and Simson reflectors that are originally intended for normal bulbs with 25 watts or 35 watts. In principle, conversion is possible, but please always observe the ABE (general operating permit). In some MZ motorcycles, such as the ETZ 250, the H4 front headlight was also fitted as standard. The average burning time of an H4 is comparable to that of a normal light bulb. In contrast, however, the light output of the H4 does not decrease significantly towards the end because no deposits form on the bulb. Incidentally, all halogen bulbs should generally not be touched by the bulb, but only by the base.

Halogen lamp

Equipping Simson mopeds and MZ motorcycles with halogen headlamp systems with halogen bulbs results in a significantly higher light output. The bulb is filled with a very precisely calculated noble gas mixture and the tungsten is extra heat-resistant. Compared to a normal bulb, no residual brown particles can settle on the edge of the smaller halogen bulb. Ultimately, this does not reduce the brightness of the light. Instead, the tungsten moves directly back to the filament as a kind of circuit. The service life of a halogen lamp for either 6 V or 12 V is correspondingly long. When installing the lamp, however, care should be taken not to touch the bulb with your fingers. The base, on the other hand, is safe to touch. Complete base plates including light and charging coil are also available for Simson S and SR models. Despite the numerous advantages, the StVZO only permits halogen lamps on public roads to a limited extent. You should therefore pay attention not only to compatibility with the two-wheeler electronics, but also to the E-mark.

Handlebar goggles

The handlebar clamp (also known as the triple clamp) is a part of the front suspension ("fork") of two-wheelers. Handlebar clamps connect the two legs of the fork with its shaft, which is mounted in the steering head and can be rotated. The steering head is in turn welded to the chassis of the two-wheeler. Handlebar ends owe their name to their slightly curved shape and the punched-out holes that accommodate the forks, among other things. Motorized two-wheelers are usually equipped with two handlebar grilles, which increases the rigidity of the construction (i.e. its resistance to elastic deformation caused by the effects of forces or torques). On Simson mopeds and motorcycles from MZ, handlebar goggles are usually made of steel. They are wear-resistant, but should be checked for deformation or cracks after accidents and replaced if necessary.

Headlight

Colloquially, the complete front lamp of a two-wheeler is often referred to as the headlight. The actual headlight is therefore also referred to as the headlight insert. It consists of a reflector and a glass lens. The reflector serves as a holder for the Bilux bulb and the parking light bulb. It focuses the light. The diffusing lens refracts the focused light and distributes it. This ensures good illumination of the road without dazzling oncoming traffic more than necessary.

Headlight housing

The headlight ring is available in as many different versions as there are headlights. On some models, such as the Simson mopeds from the Vogel series or the ES/2 models from MZ, the headlight ring is simply a plastic cover that conceals the headlight insert holder. On other models, the headlight insert is fixed in the headlight ring and thus connected to the housing. On other models, the headlamp ring connects the headlamp insert to the lamp housing in a similar way to a cranked hose clip.

Headlight ring

The headlight housings on Simson and MZ are very different. On the Schwalbe, for example, the headlight housing is part of the fairing. The situation is similar on the ES models from MZ and the rest of the Simson Vogel series (all models with front swingarm), where the tank and lamp form a single optical unit. On models with telescopic forks, the headlight housing is a lamp pot. Depending on the model and series, the headlight housing also houses the ignition lock and sometimes the speedometer.

Heart box

On Simson mopeds, the middle section of the air filter housing is known as the heart box - a name that this component owes to its characteristic outer shape, which is reminiscent of a heart. Other common names are air filter box, battery box and middle section of the housing. The air filter of Simson mopeds, whose housing includes the heart-shaped box, has the task of cleaning the air of tiny particles before it reaches the carburetor or the cylinders. The heart box contains the air filter box, a device for holding the air filter cartridge, which is protected by a cover plate. Heart boxes for Simson mopeds are made of plastic and differ slightly in size depending on the vehicle type for which they were manufactured. They are closed on both sides with a side cover. Heart boxes are largely maintenance-free. However, the air filter cartridge in the heart box must be replaced from time to time. On this occasion, the numerous small parts attached to the heart box (such as the intake sleeve, battery holder and hole cover) should be checked to ensure that they are secure.

Heat protection

Heat shields are components used on motorized two-wheelers to cover the exhaust pipe. They are also used on Simson and MZ two-wheelers. As the exhaust pipe of motorcycles and mopeds is usually exposed, it poses a risk to the rider. To prevent burns from accidental direct contact with the pipe, it is fitted with heat protection. This is a semi-circular steel plate that is placed around the side of the exhaust pipe facing outwards. Openings are punched into the sheet steel so that the heat escaping from the exhaust pipe does not build up and the pipe is cooled by the airstream. The heat shield is attached to the front and rear of the exhaust pipe using special fastening clamps. When maintaining and caring for the heat shield, it should be borne in mind that its exposed position means that it is particularly exposed to splashing grit (all year round) or road salt (in winter), which makes it particularly susceptible to damage and therefore corrosion. To ensure the safety of the driver, the tight fit of the heat protection fastening clamps should be checked regularly.

Hub

Hubs are machine elements that are pushed onto shafts or axles on two-wheelers. While shafts not only support the hub but also transmit the rotational movement and torque, axles have a purely bearing function. Whether the two-wheeler has shaft-hub or axle-hub connections depends on whether it has front-wheel, rear-wheel or all-wheel drive. Two-wheelers with rear-wheel drive, for example, are equipped with an axle-hub connection at the front and a shaft-hub connection at the rear. MZ motorcycles and Simson mopeds generally have rear-wheel drives. Hubs for MZ and Simson two-wheelers are available as individual components or as part of complete wheels consisting of tires, rims and hubs. In the case of hubs for Simson mopeds, there is also a choice between hubs with and without pre-assembled wheel bearings. Hubs are wearing parts that should be serviced at longer but regular intervals (approximately once a year or every 30,000 kilometers) and replaced if necessary. If the wheel bearing, which is particularly susceptible to wear, is not pre-mounted on the hub, it can also be replaced separately.

Idle nozzle

The idle jet is often referred to as the secondary jet (ND) and is an important carburetor component. As the name suggests, it is used to prepare the fuel mixture in the idling system or at idle speed. It also has a decisive influence on the part-load range and requires optimum adjustment for smooth starting from idle speed. The idle jet setting should be checked regularly in order to avoid so-called "potholes". An ND that is too small or dirty can quickly lead to blockages and the engine dies. It is therefore also important to clean them as thoroughly as possible. Idle nozzles that are too large are often responsible for the engine stalling at low engine speeds. Depending on the load, it may not be possible to completely avoid replacing them in certain cases, as the idle jet belongs to the wear part group.

Idler wheel

The idler gear is a component of the transmission of motorized two-wheelers, among other things. It is used on both Simson mopeds and MZ motorcycles. Gears are used for power transmission. The idler gear is a component of the shift drum, which is used for shifting (changing gears) in sequential gearboxes. Sequential transmissions are transmissions in which it is only possible to shift to the next lower or next higher gear, but it is not possible to skip gears. Sequential transmissions are used in motorcycles and a few other motor vehicles. Motor vehicle transmissions are generally gear transmissions in which power is transmitted from the drive shaft via the countershaft to the output shaft, with the shafts meshing via gear wheels. A fixed gear and a gear that is loosely connected to a shaft form a pair. The fixed gear is called the fixed gear and the loose gear is called the loose gear. When the fixed gear meshes with the loose gear, the force is transferred from one shaft to the other. Like the gearbox as a whole, idler gears are lubricated, but are otherwise maintenance-free.

Ignition coil

The ignition coil works on the principle of magnetic induction and is responsible for generating the high-voltage pulse which then triggers the spark at the spark plug. This high-voltage pulse is achieved by two different windings, which are wound around a common iron core within the ignition coil. The different wire thicknesses and number of turns in the primary and secondary windings ensure that the battery voltage is transformed into the high-voltage range. Depending on the ignition coil type, the winding ratio is between 1:150 and 1:200. The normal operating voltage is applied to the primary coil. A strong magnetic field builds up around the iron core and the primary coil. If this voltage is switched off by the lower cup or an electronic ignition module, this magnetic field collapses and a high voltage is induced in the secondary coil by the field change, which triggers the decisive ignition spark

Ignition contact

The ignition contact is often also called the breaker contact, ignition interrupter or simply breaker. It is a mechanical switch that is opened once per crankshaft revolution by a cam. When opened, the ignition contact interrupts the voltage on the primary winding of the ignition coil and thus triggers the ignition spark. The ignition contact is located on the breaker plate. The unit can be rotated axially through slotted holes in this plate. This makes it possible to set the correct ignition timing. The ignition contact is a wearing part. On the one hand, the electrical contact surface burns off over time, and on the other, the actuating hammer on the cam ring wears down. In modern engines, the mechanical breaker has long since been replaced by contactless Hall sensors and an electronic ignition system.

Ignition light switch

The Simson and MZ two-wheelers were equipped with so-called ignition light switches. As the associated keys were standardized models, they were hardly used for theft protection. Only the plug lock in the steering head was responsible for this. The ignition light switch fulfilled several tasks. Depending on the position of the "ignition key", either only the ignition is on, or the ignition plus parking lights or the ignition plus the complete lighting system. A further position switches only the parking light on, whereby the ignition key can be removed. On the models of the ES and TS series from MZ, there is a special position in the ignition light switch. In simple terms, the electromechanical regulator is bypassed and the current from the alternator is fed directly to the ignition system. This meant that these models could be started quite easily in the event of a discharged or defective battery.

Ignition lock

Simson and MZ, at least in the GDR, did not have a real ignition lock, as we are used to from cars or western motorcycles. An ignition lock worthy of the name was only installed on some models after "reunification". The GDR models had an "ignition light switch", which was also operated with a kind of key, but this "key" was a standard model and could be bought by anyone for a few pennies. A narrow screwdriver or the letterbox key on the key ring also fulfilled this function with a little "fiddling".

Ignition system

In combustion engines, the ignition system is the device for igniting the fuel-air mixture in the cylinder combustion chamber. Ignition systems can be found on all motor vehicles. On Simson mopeds and MZ motorcycles equipped with petrol engines, ignition is achieved by generating an ignition spark that ignites the fuel-air mixture. Depending on the design and model, there are different methods for this. The ignition systems used in Simson mopeds and MZ motorcycles are mainly magneto and electronic ignition systems. Magnetic ignition systems do not require an electrical energy storage device (such as a battery or accumulator) to trigger the ignition process, as the electrical energy required to generate the ignition spark is generated by an electrical generator driven by the combustion engine. Magneto ignitions were the standard ignition system for motor vehicles until the 1960s, but have since been gradually replaced by electronic ignition systems, which have also been used on more recent Simson mopeds and MZ motorcycles. Electronic ignition systems have an electronic control unit that calculates the ignition timing and triggers the ignition by sending an electronic signal instead of the breaker installed in magneto ignitions. The contact breakers of magneto ignitions wear out and have to be replaced from time to time. The electronic control components of electronic control systems, on the other hand, are not susceptible to wear.

Ignition timing

Ignition timing is not usually defined as the time at which the spark from the spark plug actually starts the combustion process in the combustion chamber, but rather the time at which this process is triggered by the interrupter or the ignition electronics sensor. Since a few milliseconds elapse between the time of triggering and the time of ignition of the compressed gasoline/air mixture, regardless of the engine speed, the ignition timing must be set shortly before the piston reaches top dead center. The delay in the ignition coil is approximately one millisecond. The time between ignition of the combustion and the maximum expansion of the explosion in the combustion chamber is another two to three milliseconds. The optimum ignition timing is therefore directly before top dead center (TDC) is reached. The mixture is compressed to the maximum and expands with maximum effect once the TDC has been exceeded. The correct ignition timing is specified either in ° (degrees) of the crankshaft position before TDC, or in millimeters of the piston before TDC. The optimum ignition timing varies from model to model and depends on the rated speed and ignition type.

Individual acceptance

This is necessary for vehicles that deviate significantly from the standard type due to extensive modifications. Furthermore, any damage that has previously been criticized is also checked for proper repair via individual acceptance. The inspection is carried out by a technical inspection organization.

Insulating flange

KBA - Federal Motor Transport Authority

Issues the ABE and ABG (national) as well as the EC/ECE type approval "E1" for motor vehicles and vehicle parts. It also maintains the central traffic register (traffic offender file).

KBA number

The KBA number is a unique number under which a vehicle or a component is registered with the Federal Motor Transport Authority.

Kickstarter - Kickstarter shaft

The kick starter is a fold-out lever that is used to bring the engine up to the speed required for starting. For this purpose, there is a foot lever ("pedal") at the end of the kick starter, which is operated with a few firm kicks. At the end opposite the pedal, the kickstarter is connected to the kickstarter shaft. It transmits the force released when the kickstarter is operated either to the crankshaft (with the primary kickstarter) or to the so-called transmission countershaft (with the secondary kickstarter). The starter is activated when the engine pistons have moved so far that they exceed top dead center, i.e. the highest position they can reach in the cylinder, as this is when the ignition is triggered. With some larger single-cylinder four-stroke engines in particular - including the MZ models, which have a Rotax engine - great force is required to move the piston this far. Kick starters were also installed on Simson mopeds and some older MZ motorcycles - electric starters, on the other hand, became established on more recent motorcycle models.

Knee cushion

Knee cushions belong to the group of frame parts and are fitted on the left and right side of the tank. Oval-shaped knee bolsters are particularly popular on two-wheeled vintage bikes and motorcycles from the former GDR. These include, for example, the Simson AWO Sport or AWO Touren as well as the MZ models ES, TS, RT and ETS, and as these knee pads are usually made of robust rubber, they are also known as knee pads. Opinions are certainly divided on their appearance, but they have many advantages to offer in terms of protection and comfort. Especially on bumpy roads and the associated vibrations, the padding provides noticeable relief for the knees. The tank and tank paintwork are also protected. The size of the knee pads depends on the mounting plate, which can also be ordered separately. Whether you opt for black, red or light-colored knee pads with a continuous or only partially integrated structure is of course up to the biker. Normally, there are no special approval regulations for knee pads as long as they are securely fitted.

Knee plate

On Simson and MZ motorized two-wheelers, a knee plate is a protective plate that is bolted to the frame at right angles to the vehicle axle at the front of the vehicle. Knee plates are positioned below the tank and cover the engine and manifold. They are so wide that they shield the driver's knees, which are slightly apart when seated, from the front. Knee plates are bolted to the frame. Depending on the type of vehicle, the knee plates can consist of one continuous or two individual plates and have different sized cut-outs for the tank and the manifold. The function of knee plates is to protect both the driver and the vehicle engine against splashing moisture, but above all against grit (small broken stones) and other small objects that could damage the engine and injure the driver. The knee plate can be damaged by the impact of grit and other hard objects. It may therefore be necessary to repaint or dent it from time to time.

KTA - Motor Vehicle Technical Office

Was a licensing authority of the former German Democratic Republic (GDR) based in Dresden and was affiliated to the KBA as a branch office after reunification.

Lifting disk

Simson and MZ single cylinders that do not have an offset crankshaft often have a stroke disk instead. It consists of a round disk with corresponding punched holes or notches and a pin that is primarily positioned in the middle. The term crankpin is also commonly used. These components are usually differentiated according to the positioning side on the two-wheeler. For example, there are crank pulleys with a stub shaft for the clutch side with a 17 mm long pin (MZ ES; MZ TS), for the drive side (mopeds with 50 cc - S51, S53, SR50) or for the alternator or alternator side (KR51/1, SR4, S50, SL1 mopeds). In addition to the perforation, you should pay attention to the exact dimensions (pin length, diameter) and any accessories required, such as the pulley bushing.

Lifting pin

The crankpin is one of the components of the crankshaft and is located off-center on the crankshaft axle. Connecting rods (push rods) and pistons are attached to it. The crank pins are connected to the shaft journals by so-called cheeks. Counter-rotors (MZ 1000 S /ST / ST) with in-line twin cylinders and pistons running up and down alternately are equipped with two crankpins. On the 1000 S model, the crankpin offset is 180 degrees. The crankpin offset is the distance between the crankpins, measured from the center of the crankshaft. This is used to calculate or determine the stroke of the piston. A greater distance from the center produces greater leverage and therefore more stroke. The crankpin, whether for Simson or MZ, usually also includes the matching needle bearing. Hub pins including connecting rods with needle bearings are also available as a set. The needle bearing and connecting rod thickness is particularly important here. For the ETZ125 and ETZ150, for example, it is 17.4 mm. Simson SR4-2 Star, SR4-1 Spatz and SR4-4 Habicht, among others, have a crankpin diameter of 16 mm.

Light motorcycle

A light motorcycle is a small motorcycle that has an engine capacity of at least 50 cm³ and no more than 125 cm³ and whose rated power does not exceed 11 kW in accordance with Section 2 No. 10 of the Vehicle Registration Ordinance (FZV) of March 1, 2007. In Germany, light motorcycles are exempt from registration (3 Para. 2 No. 1c FZV) and therefore also tax-free. They must bear a special registration number (Annex 4 Section 1 Para. 1 FZV) and undergo a general technical inspection every two years. When light motorcycles were included in the Road Traffic Licensing Regulations (StVZO) in 1981, other requirements initially applied: Displacement up to a maximum of 80 cm³, maximum power up to a maximum of 6000 rpm, and a maximum speed of 80 km/h, which was expected to result in safe and quiet vehicles. The current limits have been in force since 1996. Anyone in possession of a class 1b or A1 driving license, which can be obtained from the age of 16, as well as holders of a class 3 or 4 driving license, provided this was obtained before April 1, 1980, is entitled to drive light motorcycles in Germany. Light motorcycles were also built by Simson, namely the "Sperber", S70 and S83 types.

Luggage carrier

In practice, the original rear luggage racks on Simson and MZ mopeds were probably used much more often as a grab rail for the pillion rider than for actually transporting luggage. They were too narrow for this and the rubber strap only worked in one direction. Losses were virtually pre-programmed. The side luggage racks were much more popular and also more functional. This allowed heavy luggage to be transported safely without shifting the center of gravity too far upwards and making the bike unstable.

Magneto ignition system

Magneto ignition system 12 volt > see also Vape A magneto ignition system is basically an alternator (Lima) with a fully electronic ignition integrated without contact. The system therefore supplies its own power. However, there are different types of magneto ignition. The early swing arm magneto ignition (SLMZ) with 6 volts was fitted as standard in the Spatz SR4-1 PK and SR4-2SK, the Star SR4-2 and 2/1, the Schwalbe KR51/1 and the Simson S50 N and B, among others. The capacitor (to minimize sparking), breaker, ignition coil and two light coils are connected directly to the base plate and the ignition spark is generated by a mechanical breaker contact driven by the pole wheel cam. This very simple flywheel magneto ignition was replaced by the flywheel primary ignition (SLPZ) and later by the flywheel electronic ignition (SLEZ). The reliable VAPE magneto ignition systems are very popular for conversion to 12 V because they are largely maintenance-free. They also have an enormously high performance potential. 12 V magneto ignition systems from Powerdynamo are also frequently used, for example for the MZ models ES, ETS and TS. However, magneto ignition systems with 6 volts are also still available. A complete conversion kit is worthwhile for replacing the original electronic ignition or the alternator including ignition coil and breaker. Depending on the version, this includes the base plate, regulator and ignition coil, the flywheel and the appropriate cables. Optional sets with an additional range of lamps, flasher unit, plug and retaining elements, horn and 12 V battery are also available. As always, the ABE must be observed for all conversions.

Main nozzle

The main jet installed in the carburetor is often abbreviated to HD in specialist circles. It is the largest jet in the float chamber. It is primarily responsible for ideal mixture formation at full throttle, i.e. when the corresponding slide valve reaches its highest position. If the HP is too small, the cylinder usually overheats because the mixture is too lean. If the main jet is too large, the proportion of gasoline in the now too rich mixture increases and the engine begins to stutter under full load. When replacing the original HP to increase performance, it is therefore always important to ensure optimum fine-tuning. The corresponding spark plug pattern is generally helpful here. Regular maintenance and cleaning intervals are also essential.

Master brake cylinder

The brake master cylinder, or master cylinder for short, is a cylinder that is used to generate pressure. It first transfers the force to the brake fluid. This causes the force to be transferred to the pistons in the brake calliper. The pistons in turn press against the brake disks. If the pistons are stuck (e.g. after a very long service life), the brake cylinders, pistons and, above all, all seals should be cleaned thoroughly and, of course, according to precise instructions. However, if the components are badly damaged, it is worth replacing the brake master cylinder including all affected accessories. These are available for MZ (e.g. ETZ and TS) and for Simson individually, with handbrake lever or as a set. It is essential to ensure that the pistons and the cylinder are precisely matched in size, as the Simson models S50, S51 and S70, among others, have drum brakes as standard, which are often noticeable due to a reduction in braking effect. With the appropriate specialist knowledge, they can be converted to disc brakes with a suitable brake master cylinder.

Moped

The term "moped" covers motorized two-wheelers and three-wheelers that have the following characteristics: They are motor vehicles with a maximum design speed of 45 km/h and an engine capacity of up to 50 cm³ or with an engine power of up to 4 kW in the case of electric motors. The term "moped" was first introduced in 1953. Since then, the legal requirements have changed several times. Today, mopeds are defined uniformly throughout Europe in the EC vehicle classes L1e and L2e. The types of motorized two-wheelers that are classified as mopeds are bicycles with an auxiliary motor, mopeds, light mopeds, mopeds, mopeds and scooters. Three-wheeled mopeds are mainly vans such as the Ape and the Microcar as well as ambulances such as the Simson Duo. Driving mopeds requires an EU driving license category AM, which can generally be obtained from the age of 16, in the federal states of Thuringia, Saxony and Saxony-Anhalt as part of a pilot project from the age of 15. Mopeds are not permitted to drive on freeways, as this requires a maximum design speed of at least 60 km/h. Simson also produced mopeds. To this day, the Simson S50/51 is the most frequently built moped in Germany.

Needle nozzle

The needle nozzle is one of the components of the carburetor and is located in the upper nozzle block area. The needle jet system, which regulates the mixture composition, particularly at part load, also includes part load and jet needles. While the needle nozzle and nozzle block cannot normally be adjusted, the nozzle needles are adjustable. A needle that hangs higher by means of notches makes the mixture richer. The lower needle ensures a leaner mixture. Due to the pulsating gas flows, the needle nozzle wall can gradually become larger. As a wear element, the needle nozzle must therefore be replaced in good time. The part-load needle and needle nozzle should always be regarded as a single unit and both components should be replaced at the same time.

Nozzle gauge

Jet gauges are hardened steel pins that are set in so-called plastic blades. They serve as a practical tool for checking or adjusting the individual jets and therefore belong to the group of tools for maintenance work on the carburetor. With the help of these pins, most inconsistencies, such as deviations in the jet diameter or signs of wear, can be detected quickly and easily. They can also be used to expose jets that have become unrecognizable. Nozzle gauges are available as a set for Simson and MZ in sizes from 0.45 mm to 1.50 mm or from 1.50 mm to 3 mm and are naturally part of the basic equipment of passionate mechanics.

Oil filter wrench

Oil filter wrenches are available in numerous designs. They make it relatively easy to open the oil filter and therefore belong to the group of tools used for oil changes or similar maintenance work. While the so-called oil filter spiders are primarily suitable for cars, universal oil filter wrenches with steel bands are used for motorcycles and mopeds. They are infinitely adjustable and can therefore be used for almost all MZ or Simson models. This means that you do not generally have to pay attention to the oil filter size. In addition, the oil filter wrench replaces the complicated procedure with a screwdriver. There are also comparable versions with fabric tape. However, these are less robust than the steel or metal strap types.

On-board tool

At Simson and MZ, the on-board tools were not just real emergency tools like today, but were sensibly and thoughtfully put together. There was no wide network of workshops and no ADAC. Smaller repairs were carried out by the native GDR citizen himself. This did not only apply to the simple replacement of spark plugs, a Bowden cable or a light bulb could also be changed without any additional special tools. Even removing the carburetor for cleaning purposes or dismantling a wheel and repairing the hose was possible with the on-board tools at the roadside. The tool kit was either stored under the left side cover next to the battery or under the folding seat. The tool kit contained: two mounting levers, double open-end wrenches (8 and 9 mm, 10 and 13 mm, 12 and 14 mm, 17 and 19 mm), spark plug socket wrench, 10 and 13 mm socket wrench, hook wrench for the manifold, small and large slotted screwdriver, combination pliers, feeler gauge and a spare plug. The number and size of the double open-end wrenches varied depending on the type. The combination pliers were also not included with every model.

Output shaft

The output shaft is responsible for tapping the torque generated on the transmission. Among screwdrivers, it is also known as the output shaft or pinion shaft. The output shaft is sealed to the engine block with an oil seal, and this component, which is part of the gearbox, is available for the 3-speed Simson S50, KR51/1 (Schwalbe) and Star SR4-2 models, as well as with twelve holes for the 4-speed Simson S51, S70 and SR50 mopeds. For the MZ motorcycles ETZ 250, 251 and 301 as well as TS 250 and 250/1, you can even draw from remaining GDR stocks. When changing the output shaft, you should of course not only consider the accuracy of fit, but also the necessary accessories. These include, for example, the ball sets, spacer washer and shift fork, the sealing caps, springs and circlips.

Parallel pin

Dowel pins are tools for connecting two workpieces. They are also used on motorized two-wheelers, including Simson mopeds and MZ motorcycles. Generally speaking, pins connect components in a radial direction (the pins) by inserting them through holes that pass through all the components to be connected. The pin is prevented from falling out of the hole by a frictional connection. Cylindrical pins are - as the name suggests - cylindrical in shape and usually have rounded or chamfered (i.e. beveled) edges. Pins of this type are used for position-locking connections that rarely or never need to be loosened. Cylindrical pins are used on Simson mopeds and MZ motorcycles in very different areas, for example in the engine, carburetor and float.

Partial load needle

The part-load needle is an important component in the slide carburetor. It is mounted in the round slide (on very early AWO models also in the flat slide) and sits with its tapered tip in the main jet. In the part-load range, i.e. any throttle position between idle and full throttle, the part-load needle is raised together with the round slide and, due to its conical shape, releases an ever-increasing cross-section in the main jet. This ensures that, depending on the throttle position, the required amount of fuel is also entrained by the air flow in the intake duct. Several notches are incorporated into the upper end of the part-load needle, with the help of which it is hooked into the needle retaining plate. These notches make it possible to adjust the height in relation to the throttle valve. This allows the enrichment of the air-fuel mixture to be adjusted. If the needle is hung higher, the mixture becomes richer; if the needle is hung lower, the mixture becomes leaner. The part-load needle is a wearing part and works its way into the main jet over time. Needle and jet should always be replaced together

Piping

In vehicle construction - and therefore also on motorized two-wheelers such as Simson mopeds and MZ motorcycles - the term "piping" refers to the edge reinforcement of another object that is not firmly attached to it. Piping is usually made of rubber and is therefore also known colloquially as "rubber piping". They have the related functions of allowing a wrapped object - made of plastic, metal or glass, for example - to gently meet another object and seal the space between them. Piping is therefore also used for seals, among other things. On motorized two-wheelers, piping is used for lamp housings, scuff plates, knee plates and engine tunnels, for example. Piping is a wearing part and can become porous over time. They should therefore also be checked regularly on Simson mopeds and MZ motorcycles and replaced if necessary.

Piston

The cylindrical piston is part of the cylinder in which it moves up and down. This converts pressure into movement, which ultimately leads to propulsion. In a Simson moped, the piston travels at approx. 15 m per second at 60 km/h. The basic components of the piston include the piston crown (which holds the valves), the piston skirt (which acts as a guide in the cylinder barrel), the piston pin (connection between the piston and connecting rod) and the piston rings (sealing, heat dissipation and lubrication). On older MZ and Simson models, the pistons are still made of cast iron. Newer models already have a cast aluminum alloy using the permanent mold casting process. Safety pins are also integrated into the piston ring grooves of the two-stroke pistons to prevent jamming or twisting. On some motorcycles up to the mid-1950s, nose pistons were also used for the scavenging process and for changing the throttle. With original Simson and MZ pistons, you are almost always on the safe side. With replicas (due to lack of availability) you should always pay attention to the exact nominal dimensions. If these dimensions are undercut, this can otherwise quickly lead to major defects. The piston itself should also always be replaced in conjunction with new piston rings. Complete sets with cylinder, cylinder head, rings and pistons are also available.

Piston pin

The piston pin is the connecting piece between the piston and connecting rod. It is used to transmit power between the two components and is usually located in the piston or connecting rod eye in a floating position or with very slight play. To optimize weight, the steel pin is hollow on the inside with either a constant or centrally reinforced cross-section. On many MZ and Simson two-stroke engines, however, the piston pin bore is interrupted to avoid channel connections. Simson piston pins normally have a diameter of 12 mm and when repairs are required, replacing the piston pin alone is often not sufficient because the piston rings or even the entire piston are almost always affected. For this reason, the pin is often offered in various set variants. Depending on requirements (e.g. piston seizure = pin fit too tight), this may also include the carburetor, cylinder head and cylinder. With tuning pistons in particular, however, you should pay close attention to the StVO approval instructions. Before fitting, it is also important to check the type, displacement and dimensions as well as the number of piston rings, as there are considerable differences between Schwalbe, AWO, ETZ & Co.

Piston ring

Piston rings made of metal (Simson usually used particularly break-proof spheroidal graphite iron) are among the piston's replaceable components. In contrast to a normal ring, they are not completely closed. The small opening is also known as a ring joint. The rings also have an internal locking mechanism and the pin is located in the center of the piston ring groove. The piston ring basically fulfills three important tasks: Sealing the combustion chamber and crankcase; dissipating combustion heat from the piston to the cylinder wall; metering lubricating oil between the cylinder wall and ring. In addition to the number of piston rings, the dimensions are of course also important. On the Simson S51, for example, the piston dimensions can be found on the underside of the cylinder or on the previously cleaned piston crown. When fitting, it is also important to ensure the correct piston ring joint (distance between the piston rings). Too great a height also leads to so-called ring flutter. This noticeably reduces performance and ultimately leads to breakage. In general, it is therefore of little use to fit new piston rings to a heavily worn piston. It makes much more sense to replace both components. Ideally, piston ring pliers are suitable for fitting the piston rings correctly.

Plug-in base lamp

The plug-in base lamp is not screwed in, but plugged in. This also explains its name. In contrast to the glass bulb, which is very thin and therefore relatively sensitive, the pins are largely robust. As an instrument cluster with BAX10s base for Simson SR 50X and 80X as well as for the SRA 25 and SRA 50, they serve as a speedometer light with 1.2 watts and 12 volts. Transparent LED plug-in base lamps often have an E-mark, but this is not mandatory. This type of lamp is also used as dashboard lighting in other motor vehicles. However, it should be noted that many plug-in base lamps are not suitable as soon as an on-board computer takes over the monitoring of the bulbs. In this case, malfunctions or dropouts can quickly occur.

Plug-in coupling

A plug-in coupling for the fuel hose is often also referred to as a quick coupling or quick disconnect and is usually made of plastic. It closes on both sides and therefore also has corresponding plug-in connections at both ends. During repair work on the moped or motorcycle, the plug-in coupling is used to automatically seal or close the fuel line. This effectively prevents unwanted fuel leaks. However, it is essential to pay attention to the internal and external connection dimensions. Simson fuel hoses usually have an inner diameter of 4.7 mm or 6.2 mm and an outer diameter of 7.3 or 8.8 mm. A well-stocked tool kit should never be without a plug-in coupling.

Pole wheel - flywheel

The pole wheel is a part of the ignition system and alternator of motorized two-wheelers. It is located above the so-called base plate, to which an ignition coil and two light coils (for the front headlight and rear light) are attached. The pole wheel is connected to the crankshaft via a woodruff key, also known as a "half-moon key". The main function of the pole wheel is to create a magnetic field that generates voltage in the three coils attached to the base plate. For this purpose, magnets are embedded in the outer ring of the pole wheel, with the positive and negative poles arranged alternately next to each other so that an alternating magnetic field is created. When this field passes the wires of the three coils, a voltage is induced in them. Due to their connection to the pole wheel, the pole wheel is also rotated and a voltage is induced when the crankshaft is turned for the first time (as happens when starting). As no external energy source (battery, accumulator) is required for starting with this method, it is also referred to as "self-induction". The second function of the pole wheel is to actuate the breaker, which switches the ignition on at the optimum ignition time and then off again. Pole wheels are installed in Simson mopeds and MZ motorcycles and are largely maintenance-free. However, care should be taken to ensure that the pole wheel does not run out of round - which can happen, for example, if the crankshaft has become distorted.

Pole wheel puller

The pole wheel puller is a relatively simple special tool for removing the pole wheel from the crankshaft journal. The pole wheel is very heavy. This mass must be accelerated and decelerated when the engine speed is changed. The hard metal spring in the groove of the crankshaft journal could not withstand the forces that occur and is only used for precise guidance. The frictional connection between the crankshaft and pole wheel is created by a conical press fit. After tightening, the nut is only used to prevent the wheel from shaking loose. A pole wheel puller is required to separate the pole wheel from the crankshaft again. After loosening the nut, it is screwed into the 26 mm internal thread of the pole wheel. A screw with a conical tip presses on the end of the crankshaft and pulls the pole wheel off the journal. Even though some hair-raising alternative methods involving jammed screwdrivers or heating with torches and light hammer blows are circulating on the Internet, there is no alternative to the appropriate pole wheel puller that does not involve the risk of serious damage to the crankshaft or its bearings.

Primary coil

The primary coil is installed on the base plate of some Simson mopeds. Like this, it is part of the ignition system. The base plate is a round metal plate on which various components belonging to the ignition system are mounted. Which components are installed on the base plate depends on which base plate model is involved. During the production period of Simson mopeds in the GDR, three main types of base plates were manufactured: Those with magneto ignition, those with primary ignition and those with electronic ignition. While the classic breaker ignition (with magneto ignition) has the ignition coil, two light coils, the breaker and the capacitor on the base plate, the base plate with primary coil has the ignition coil, which in turn is located as an external component outside the base plate and is supplied with power by the primary coil. On Simson mopeds, the primary coil should be checked at the latest during scheduled maintenance of the entire ignition system.

Push rod

The pushrod is part of the chassis assembly and is primarily used to transfer the force between the so-called pushrod cup and the rocker arm bridge. It therefore opens and closes the engine valves. The ends of the rod are rounded so that they fit directly into the ball socket of the valve tappet or rocker arm. Simson mainly installed pushrods in the AWO Touren and AWO Sport. The EMW was also equipped with them. The advantage of pushrods with corresponding pressure pieces is that they require little maintenance. Although this technology is generally regarded as outdated, it is always defended by connoisseurs due to its reliability. However, pushrods are only suitable for high engine speeds to a limited extent.

Regeneration

Regeneration is the comprehensive maintenance and care of important components of a motor vehicle - in particular the engine, cylinder, pistons and crankshafts as well as the tank. Regeneration of the relevant components is also offered for Simson and MZ two-wheelers. During regeneration, the respective component is disassembled into its individual parts, which are then cleaned and replaced if necessary. Not only worn accessory parts are replaced during regeneration, but also parts that are expected to wear out at regular intervals (such as sealing rings). Regenerations are usually offered in service packages at a fixed price. Services that exceed the respective offer are usually charged separately - for example, if the cleaning effort is particularly high or if previously undetected major damage is only discovered during regeneration. Regeneration can significantly extend the service life of engines and cylinders, pistons and crankshafts as well as the tanks of older two-wheelers and increase their performance.

Rev counter

The rev counter shows the rider the current engine speed. The luxury models from Simson and MZ also featured a mechanical rev counter. Similar to the speedometer, the rev counter was driven mechanically via a flexible shaft. Opinions differ as to whether a rev counter was really necessary on the popular East German motorcycles. Below the effective revs, the engines do not react to the throttle twist grip and above the rated revs, the engines react with an above-average noise level and heavy vibrations. Even a nervously fidgeting pointer does nothing to change this. For racing and tuning fans, however, the rev counter is more important than the speedometer. For engines that are driven at the limit, the exact engine speed is one of the most important pieces of information for the driver. Overspeeding means high wear and tear and, in racing, often the final end for the engine. Today, the engine speed can also be determined electronically. A microcomputer converts the ignition pulses into engine revolutions via a tap on the ignition coil.

Rim tape

The rim tape protects the inner tube from damage caused by the sharp edges of the spoke nipples inside the rim. Simson and MZ motorcycles are generally fitted with spoked wheels. The nipples are provided with an internal thread and a slot at the upper end. Without rim tape, the inner tube would wear through the sharp edges of the spoke nipples much more quickly than desired. The classic rim tape is a narrow strip of rubber with a punched hole for the valve. The ends are glued and the rim tape is held in position solely by the tension of the rubber. With modern, self-adhesive rim tape, it is even possible to use a tubeless tire on a spoked wheel.

Rotor

The rotor is a rotating component of the alternator and is also known as the pole or flywheel. It has built-in magnets with north and south poles and rotates around the stationary stator with copper wire windings. It is driven by the crankshaft or the belt, thus generating a three-phase alternating voltage. The conversion to direct current is carried out by a regulator and rectifier. In addition to the rotor with electromagnet, there are also rotors with permanent magnets. These are usually installed in Simson mopeds, although the efficiency of permanent magnet generators is rather limited. However, the advantages are their simple design and reliability. However, the rotor with permanent magnet should be replaced if the magnetic force is lost. VAPE rotors are significantly more heat-resistant, especially at high speeds, and also have an optional mounting device for the fan wheel. Complete conversion kits with all relevant accessories and detailed instructions are also available for a VAPE ignition system.

Separating device

If it becomes necessary to separate the two engine halves of a Simson or MZ * to overhaul the crankshaft or the gearbox, a separating device is required. The crankshaft bearing and the bearing of the output shaft are fixed both on the shafts and in the housing. This means that the housing halves cannot be easily separated from each other even after all the connecting screws have been loosened. A separating device works on the principle of a puller. Several screws are screwed into the thread of the housing half through a pressure plate. Two further threaded holes are positioned so that the tip of the pressure screws presses on the crankshaft journal or the output shaft. By tightening the pressure screws evenly and gradually, the housing half is removed without damaging the material. There are also instructions on the Internet for separating the engine housing without special tools, but this usually causes considerable damage and ruins the engine for good. * This is about the standard models from GDR production. The AWO's and some later models have different engines.

Shaft seal

Radial shaft seals are also known colloquially as Simmerrings. However, this term is merely a registered trademark whose name goes back to the inventor Walther Simmer. Shaft seals are used wherever a rotating shaft leaves a housing and this transition needs to be sealed. The shaft seal sits firmly in the housing and its sealing lips ensure that the shaft is sealed. The sealing lips are pressed onto the shaft surface by a tube spring (worm spring). On motorcycles with telescopic forks, shaft seals are also used to seal the upper shaft of the dip tube to the standpipe.

Shift drum

A gearshift drum, which enables the gears of sequential gearboxes to be shifted, can be found in Simson mopeds and MZ motorcycles with claw gears, among others. So-called grooves are milled into the shift drum, which are responsible for the axial movement of the shift claws or shift forks. If the shift drum has to be replaced due to signs of wear on the cam tracks, it is essential to ensure that there is no or only minimal axial play. It is therefore important to precisely balance the shift drum with the corresponding thrust washer. An appropriate shim usually helps to prevent too much axial play. The retaining rings and the bolt for the shifting drum should also be precisely or optimally matched.

Shift paddle

On two-wheelers, a paddle shifter is a special form of foot shift lever. On models with normal footrests, there are virtually no paddle shifters. To engage a higher gear, the foot is simply moved under the gearshift and the instep pushes the gearshift upwards via a movement in the ankle. However, this foot movement is not possible on models with footboards, where you would have to lift your entire foot to move the gearshift upwards. For this reason, the gearshift is fitted with two arms in the form of a rocker. To shift up, the rear arm of the rocker is operated with the heel. The Schwalbe is the only Simson and MZ model to be supplied with a rocker gear as standard.

Shift shaft

The shift shaft is part of the transmission. It is necessary for changing and selecting the individual gears. The Simson and MZ gearboxes are constructed very differently. On MZ motorcycles, the gearshift shaft is a straight, smooth shaft. At the outer end, the foot shift lever sits on a toothing. Inside the gearbox, a gearshift unit moves a cam roller which engages and locks the corresponding gear. Simson mopeds are equipped with a splined gearbox. Here, a key is moved by means of a grooved shift shaft when changing gear and the corresponding gear wheel is locked. In this case, the foot shift lever does not sit directly on the shift shaft. The movement of the shift lever is transferred to the shift shaft via a mechanism in the clutch housing.

Shrink tubing

Shrink tubing is a thermoplastic tube that shrinks under the influence of heat (hot air dryer, lighter). It is mainly used for repair work on Simson and MZ electrics. With a shrink ratio of 2:1 and a shrink temperature of approx. 120 ºC, it is used, for example, to insulate bare cables. After shrinking, the tubing is also temperature-resistant and also offers particularly reliable corrosion protection. Heat-shrink tubing is available in various lengths and with different wall thicknesses. Anyone who wants to carry out extensive insulation work on their motorcycle or moped electrics is well advised to purchase a complete set.

Sliding gauge

The caliper gauge is somewhat better known as a caliper gauge or caliber. A steel caliper gauge for motorcycles and mopeds from MZ and Simson normally consists of a flat bar with a millimeter scale, two measuring legs and a movable slider. If you find reading the scale too complicated or need measurement results not only in millimetres but also in inches or in 0.01 mm increments, you should opt for a battery-operated digital slide gauge with display. This also allows you to set 0 positions and display plus/minus values. A caliper gauge can be used to determine the sizes of springs and screws as well as distances and fits to the nearest millimeter.

Soffitte

The name Soffitte is primarily based on the cylindrical design. To use this light source, the lamp base must also meet the corresponding requirements, as the festoon lamp has a contact device at both ends. On two-wheelers, festoons with a filament are still occasionally found in tail lights and license plate lights and more frequently in the blinker systems. In this case, they are often offered as a set including blinker caps. According to the StVZO, however, there are severe approval restrictions. Without a K-mark or ECE, festoons that are not used exclusively as interior lighting are not permitted.

Spark plug connector

The spark plug connector, also known colloquially as the spark plug cap, establishes the high-voltage connection between the ignition cable and the spark plug. In addition to the electrical connection via a mechanical spring terminal, the spark plug connector also has an interference suppression function. Simson and MZ use spark plug connectors with 1 kilo-ohm interference suppression resistance. Although interference suppression is not necessary for the function, interference-free ignition systems cause interference in radio reception in the immediate vicinity.

Splined shaft

A splined shaft is a component of certain types of transmission used on some motorized two-wheelers (especially light motorcycles), including Simson mopeds. Splined shafts are characterized by the fact that the positive connection to the hub of a shaft-hub connection is made by dogs with straight and parallel flanks - in contrast to splined shafts, where the flanks of the dogs are involute. The number of dogs depends on the number of gears of the respective operation. In the splined shaft, the gears are engaged and disengaged by the so-called spline. It is inserted into the internally drilled splined shaft via a milled window, where it is moved by a rod. Depending on the position of the drawing wedge, the gears are positively connected to the drawing wedge shaft. Due to the constant engagement and disengagement of the gears, as is usual in normal driving, splined shafts wear out and must therefore be replaced if there is too much "play" during the shifting process and the gears can no longer be engaged without problems.

Split pin

Visually, the split pin resembles a standard hairpin. It is used as a fastening and securing element on Simson, MZ and IWL mopeds, scooters and motorcycles. The simple one-way split pin, which is straight on both sides, is particularly easy to remove, but must not be used again afterwards. A permanent cotter pin has one straight and one corrugated side. Although it is usually more complicated to remove, it can be used several times and is predestined for particularly safety-relevant applications. Cotter pins are used, among other things, for brake block mounts, for the steel tilt stand, for bearing bolts on the foot brake lever, for securing screw connections and for shift rods. Although the cotter pin is actually a comparatively inconspicuous element and in some exceptional cases you might even ask yourself whether it makes sense or not, it is important, at least from a legal point of view. If the cotter pin securing device is registered in the ABE, it will also be given decisive attention during the main inspection. You should therefore think very carefully about whether replacing a split pin, for example with a self-locking nut, is a good idea. Of course, you should always pay attention to the exact dimensions. For MZ and Simson, cotter pins are available individually or as a complete cotter pin assortment in a box for frequent screwdrivers.

Spring elbow

Spring manifolds are part of an innovative exhaust mounting system that can be retrofitted to Simson mopeds and scooters. The use of spring manifolds is one way of eliminating a problem that occurs on numerous Simson models: On older scooters in particular, the exhaust is firmly bolted to the engine with a two-point attachment. As the engine (which itself rests on soft rubber mounts) moves by several centimeters when the scooter is running, the exhaust is also set in vibration, but cannot move freely enough due to the rigid two-point mounting. As a result, the individual components of the exhaust suspension "work" hard. The manifold nut in particular loosens under the influence of the permanent vibration and has to be retightened regularly (every few hundred kilometers according to experience reports). If, on the other hand, the exhaust is secured with spring manifolds, the vibration emanating from the engine is considerably dampened and at the same time ensures that the exhaust can resonate freely. Spring manifolds are hooked into the ball flange on one side and into the holes provided for the damping rubbers on the cylinder on the other. Spring manifolds are wearing parts and should be serviced regularly and replaced if necessary. They are usually supplied as a set with all the components required for the conversion.

Sprocket - Sprocket

The small sprocket is the driven (motor-side) of the two gear wheels on two-wheelers with a chain drive. The correct technical term for this component according to DIN is "sprocket", although this term has not become established in everyday language for motorized two-wheelers. The small sprocket is connected to the shaft via a hub and transmits its torque via the drive chain to the driven sprocket, which is usually located on the rear wheel of motorcycles and mopeds. The small chain sprocket is also referred to as such if it actually has a larger diameter than the driven sprocket. MZ motorcycles and Simson mopeds, which are equipped with a chain drive, also have small sprockets. When caring for and maintaining them, it is particularly important to ensure that the drive chain is always sufficiently lubricated, as otherwise the small sprocket will also wear out more quickly. The small sprocket must be replaced as soon as its teeth start to become blunt, otherwise the drive chain could lose its tight fit.

Sprocket driver

The sprocket driver is the one of the two sprockets on two-wheelers with a chain drive to which the power is transmitted. It is therefore the driven sprocket of the sprocket pairing. Its counterpart is the drive sprocket (also known as the small sprocket on motorized two-wheelers), which transmits the power to the sprocket driver via the drive chain. The DIN term "sprocket" has not become established in colloquial language for two-wheelers. Sprocket drivers are also installed on MZ motorcycles and Simson mopeds, which have a chain drive. As most motorized two-wheelers are equipped with a rear-wheel drive, the sprocket driver is usually located on the rear wheel and is therefore also called the "rear sprocket driver". It is pushed onto the hub, which in turn is connected to the shaft of the rear wheel. It is crucial for the maintenance of sprocket drivers that the drive chain is always well lubricated, otherwise the teeth of the sprocket driver will wear out quickly. The sprocket driver should be replaced as soon as its teeth become blunt.

Standard parts

Standard parts are those components of motorized two-wheelers that are defined in a technical standard. Standards are issued by government institutions entrusted with the task of standardization, in Germany primarily by the German Institute for Standardization (DIN). The aim of standardization is to standardize the objects described in the standard, thereby making them usable for a large number of applications and thus reducing manufacturing costs. The counterpart to the standard parts are the work parts that are produced by a specific manufacturer for use in its own products. Standard parts, on the other hand, are generally not produced in-house but purchased from specialist manufacturers. Typical standard parts used in motorized two-wheelers include nuts and bolts, springs and seals, cables and resistors. Simson mopeds and MZ motorcycles also use numerous standard parts. A special feature is that these standard parts were standardized according to the East German Technical Standards, Quality Regulations and Delivery Conditions (TGL) before 3 October 1990, but have since been standardized according to DIN. The transition from TGL to DIN was simplified by the fact that numerous TGLs corresponded to DIN standards in order to enable GDR mechanical engineering companies to export to the West.

Strainer

The mud flaps are riveted to the rear ends of the mudguards. As the name suggests, they are designed to catch dirt and moisture whirled up by the wheels. In the GDR, the moped was often the only means of motorized transport. It had to be used every day and in all weathers. The mud flap on the front mudguard protected the moped and the rider. On the rear mudguard, it protected the traffic behind. The newer mud flaps are made of relatively soft plastic. Older models were often fitted with so-called splash guards made of rubber

StVO - Road Traffic Regulations

Legal basis for behavior in road traffic. Includes regulations for drivers of motorized vehicles as well as for pedestrians and cyclists.

StVZO - Road Traffic Licensing Regulations

Regulates the formal and technical requirements for the registration of vehicles. It is divided into three parts: 1. registration of vehicles in general 2. operating permit and type approval 3. construction and operating regulations

Suspension strut

A suspension strut essentially consists of two components. One is the actual spring and the other is the shock absorber. The spring compensates for bumps in the road, the shock absorber brakes the spring and thus prevents the chassis from rocking. Depending on the version, both Simson and MZ fitted partially adjustable suspension struts. Depending on the load, the rider can adjust the preload of the springs in stages and thus adapt the road holding to the payload.

Swing arm

The swingarm connects the rigid frame of the motorcycle to the axle of the rear wheel. The MZ - ES models also have a sliding swing arm on the front wheel. The swingarm has a load-bearing function in the chassis. In conjunction with the suspension struts, the swingarm compensates for uneven road surfaces. The swing arm is mounted on the frame in the swing axle and can be moved up and down at right angles to the direction of travel. The wheel axle and the chain tensioner guide are located in the rear slot of the swingarm. The swingarm itself is not subject to wear. Even the swingarm bearing on the suspension on the frame should last the life of the moped in most cases.

Switching claw

In transmissions with claw gears, the shift claw ensures the frictional connection between the individual gear pairs of the corresponding gear. Gear wheels that are not firmly connected to the shift shaft are shifted at right angles to the direction of rotation. The shift claws engage and thus ensure power transmission between the gear pairs of the selected gear. Visually, the shift claws can also be imagined as the embrasures of a round, medieval watchtower, which are attached to the side of the gearwheel and engage with a matching counterpart. However, the term shift claw is also used colloquially for various other gearshift components that look like a claw but are actually called shift fork, shift piece or actuating claw.

telescopic fork

The correct technical term for telescopic fork is actually telescopic fork. Two telescoping tubes form a fork leg. Two of these fork legs, which are often also called fork legs, guide the front wheel and also act as shock absorbers. Each fork leg consists of a stanchion tube and a lower tube. The lower tube is often also referred to as the sliding tube. The stanchion is attached to the fork crown. Inside the stanchion tube is a helical compression spring, which serves as a suspension spring, as well as the damper tube and the damper piston. The stanchion tube and dip tube are sealed against each other by means of a shaft seal ring (oil seal). Filling with fork oil creates a hydraulic shock absorber. The two fork legs are connected to the steering head of the frame via the fork bridge and the steering tube. The handlebars are mounted on the upper fork crown and the axle carries the front wheel between the two lower tubes.

TG - Parts certificate

Contains a list of vehicles for which the part is suitable. An officially recognized expert must approve the attachment/conversion and then issue an acceptance certificate. Without this approval certificate, the operating license expires.

Thread gauge

The thread gauge for metric threads on MZ and Simson is also known as the thread comb or thread template. It is used to check the internal threads using the light gap method. This fan-shaped template can be used to check the flank, core and nominal diameter as well as the flank angle position and the flank angle pitch. The gauge is simply placed on the thread and then held up to the light. With a suitable thread, no light should shine through. However, exact deviation values cannot be determined with this thread gauge. Nevertheless, they are ideal as an on-board tool and should not be missing in cutting boxes or in a well-equipped workshop.

Throttle cable

The Bowden cable that connects the throttle twist grip to the slide in the carburetor is also known as the throttle cable. Turning the throttle handle raises the carburetor slide, the air volume in the intake duct increases, more fuel is drawn in and the moped accelerates. The throttle cable lasts a very long time with good care, but is still a wearing part. The throttle cable must be greased regularly and checked for damage. A stiff throttle cable cannot be operated sensitively and poses a considerable danger if it jams and no longer returns to its rest position.

Tie rod

In engine technology, a tie rod is a relatively long type of stud bolt that is used to connect the engine housing, cylinder and cylinder head. On Simson and MZ two-wheelers, apart from the rather rare four-stroke models, the tie rods are long bolts with rolled threads at each end. Stud bolts are always used in engine construction when the sensitive threads in the engine housing need to be protected from damage. Motor housings are usually made from cast aluminum. Aluminum is a very soft material. Screws and bolts, on the other hand, are made of steel, which is much harder. In addition, contact corrosion often occurs between the different materials. As a rule, a stud bolt is only screwed into the cast aluminum once during initial assembly and only needs to be loosened on the opposite side to replace the fastened components. If a screw were used in the same place, there would always be a risk of ruining the thread in the expensive motor housing. When working on the tie rods, as with all other stud bolts, the prescribed tightening torque must be carefully observed.

Trademark badge

Trademark badges for the Simson bird series, such as the Schwalbe, the Starling, the Habicht, the Spatz and the Sperber, can be recognized by the red lightning bolt on a white background. The original "Simson" lettering is located directly above it, completing the well-known logo. These aluminum badges are available in gold or silver. They can be easily attached to the handlebar shell by inserting the metal strips into the shell openings and then bending them over. To prevent the badge from coming off again after a short time, the handlebar shell should be thoroughly cleaned and dried beforehand. This makes the unmistakable logo an absolute eye-catcher for every Ostalgiker and loyal Simson fan.

TÜV - Technical Inspection Association

Is a registered association that carries out safety inspections as a technical testing organization in accordance with state laws or regulations. The best known of these is the general inspection of motor vehicles.

Two-stroke engine

Two-stroke engines are internal combustion engines in which a fuel-air mixture is first compressed and then burned, with combustion being initiated by spark ignition (by means of the spark plug). Two-stroke engines are used in motor vehicles, including Simson mopeds and MZ motorcycles. The design of two-stroke engines is very simple, as they essentially consist only of the crankshaft with connecting rod and piston as well as the cylinder (with the intake and exhaust ports for the fuel-air mixture). A characteristic feature of two-stroke engines is that one working cycle consists of two piston strokes. When the piston moves upwards (1st stroke, compression/intake), a vacuum is created in the crankcase. The fuel-air mixture flows into the crankcase via the mouth of the intake port, which is released at the same time. Meanwhile, the piston compresses the fuel-air mixture in the working cylinder, which is finally ignited - near top dead center - by the spark from the spark plug. The pressure generated by the combustion of the gas drives the piston downwards again (2nd stroke, working/precompression). This closes the intake port and at the same time pre-compresses the mixture in the crankcase. At bottom dead center, the piston releases the exhaust port so that the burnt gases (exhaust gases) can escape. At the same time, it allows the pre-compressed fresh fuel-air mixture to enter the working cylinder via the so-called top flow channel. The advantages of the two-stroke engine include low manufacturing costs due to its simple design, low wear due to the small number of moving parts and high engine speeds. Two-stroke engines are the most widely used type of engine for mopeds, such as Simson mopeds.

Type plate

The type plate is a small aluminum plate that is riveted to the frame and on which some important information about the vehicle is printed or embossed. The manufacturer is printed at the top of the Simson and MZ type plates. Below this are four fields on which the model designation, the year of construction, the permissible total weight and the chassis number are noted. At the bottom is often the note "Made in the GDR" or "Made in German Democratic Republic". Different texts can be found depending on the manufacturer and year of construction. Some nameplates also feature the number 1 in a triangle with rounded corners. This is a seal of quality of the GDR and corresponds to "quality class 1". Products that were of average quality on the world market bore this seal.

Vape

The Czech company VAPE specializes in the manufacture of ignition and control systems as well as voltage regulators and alternators for motorcycles. When VAPE is mentioned for Simson and MZ, it usually refers to a particularly powerful 12-volt ignition system. It was originally installed in the S53 and S83, among others. As the Vape is almost maintenance-free, countless mopeds are now being converted to VAPE 12 V. However, one of the few weak points of a Vape ignition is the regulator. In the worst case scenario, this can go bye-bye. The magnets could also come loose from the pole wheel. Otherwise, however, the vape system scores points with its extra high reliability and significantly better light output, and the vape conversion of a 6 volt contact ignition in older MZ models is extremely advantageous from today's perspective. 70-5 with 110 watts and 70-3 with 100 watts are absolutely sufficient for equipping with H4. For conversion, for example on a Simson S50, S51, S70, KR 51/1 and 51/2 (Schwalbe), SR4-4 (Habicht) or an SR4-2 (Star), we recommend a complete conversion kit with or without horn, battery and bulb. Of course, individual components are also available. This also includes the somewhat fragile regulator. However, you should have a very good knowledge of electrics for the conversion and never start without precise instructions and a circuit diagram. For less experienced hobbyists, it is definitely worth going to a specialist workshop.

Wheel bearing

The wheel bearings are located between the wheel hub and axle. Two bearings are always installed per wheel. They ensure that the wheel can rotate easily and without play on the axle. Ball bearings are installed here on all Simson and MZ models. Even if the wheel bearings last quite a long time, they are still wearing parts. To check the wheel bearings, the moped is jacked up on the main stand and the corresponding wheel is relieved. Then grab the wheel by the tire and try to move it at right angles to the direction of travel. No play should be detectable. As the wheel bearings are a tight fit in the hub, replacing them is not so easy. Experienced mechanics carefully(!) heat the wheel hub and cool the new wheel bearings in the freezer compartment or with cold spray. If you use brute force here, you will very quickly damage the bearing surface of the aluminum hub when hammering it in.

Whitewall tires

The first rubber tires were all white. They were made from natural rubber and white is the natural color of this material. To make the tires more durable, more and more additives were added to the natural rubber in the course of development to give them a black color. However, these additives were very expensive and were therefore initially only used on the treads of the tires. Whitewall tires were thus created for economic reasons. At that time, completely black tires were much more expensive and were considered to be noble. Today, whitewall tires are only used for visual reasons. The material is the same, it is simply dyed white. Even though neither Simson nor MZ ever offered models with whitewall tires, they are very popular with enthusiasts today. Particularly on the Schwalbe and the first-generation ES models, whitewall tires emphasize the vintage look.