Motorcycle Transmissions and Exhausts

See also Transmissions - Manual - Automatic - Chain - Belt - Shaft Exhausts - Position - Performance Engines - Stroke, 2 or 4 - Configuration Frames - Introduction - Types Suspension and Steering - Girder front end - Telescopic forks - Hub center steering - Steering dampers - Rear Shocks

Transmissions Manual transmission. Most bike transmissions are manual sequential gearboxes, with neutral positioned between first and second. After second gear each gear can only be used in order. Reverse is only fitted to the largest touring bikes like the Honda GoldWing. Automatic transmissions can be found in many scooters and some touring bikes. Chain drive is the most common form of transmission to get power from the gearbox to the rear wheel. Chains require regular maintenance and lubrication. They also require periodical adjustment and change because of the stretching incurred over time. Shaft drive is found on many touring bikes and BMW uses them on many of their models. Shaft drive units are completely enclosed and almost maintenance free, quiet and clean. Shaft drives drain power from the engine because of the complicated gearing required, they are also heavier than chains or belts. Belt drive is found on many Buell bikes among others. Belts are quiet, clean and efficient although they do stretch over time like a chain. Belts are limited in the amount of power they can handle. Back to all motorbikes

Exhausts The position of a motorcycle's exhaust can effect the bikes characteristics, especially on high speed sportsbikes. Underseat exhausts, a Ducati favorite since the famous 916, were developed to reduce windresistance by putting them up out of the airflow - good. As a by product it raises the bikes center of gravity - not good. The traditional position of exhausts, either side of the rear wheel has its advantages and disadvantages too. First of all they are not the best looking pieces of kit and can clutter up the appearance, they can also disrupt airflow and ground clearance can be in issue. But if they are positioned low they can help lower the center of gravity, they free up underseat space for storage and the engineering is thoroughly researched. Aftermarket performance exhausts can expel exhaust fumes faster permitting a longer power stroke. However, many modern production bikes already have a tuned system and an expensive performance exhaust may only operate effectively at a narrower rpm range. Louder, and often illegal, some belive that performance exhausts are safer as they can warn people who may have failed to see the bike.

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