A cam system in which the eccentrics are situated on the face of a rotating disc.
An enclosure on the front of the bike containing the windshield and affording wind protection to the rider. Can be attached to the frame and not move or be attached to the fork and move as the handlebars are turned.
Motorcycle enthusiasts may install accessories, called farkles (also spelled farkels), to customize their machine. The word is generally accepted to mean a combination of “function” and “sparkle”, hence, farkle. The term is well known in the North American sport touring community. Radar detectors, Global Positioning System receivers, heated grips, and satellite radios are some of those farkles. Other accessories could be aftermarket seats or bar risers, which make the motorcycle more suitable for long miles.
Famous Norton frame design by the McCandless brothers. It was introduced in 1950 and was given its name by factory rider Harold Daniell.
The governing body of the international motorcycle sport. Originally founded in 1904, it represents 90 national motorcycle federations that are divided into six regional continental unions.
There are five motorcycle-racing disciplines that FIM covers, encompassing 34 world championships and prizes:
- road racing
- motocross
- trials
- enduro
- track racing (combining Grass Track and Speedway)
FIM is also involved in many non-racing activities that promote the sport, its safety, and support relevant public policy.
Means of transmitting power to the driven wheel, usually by chain, shaft, or belt.
Fuel tank shape used on early motorcycles.
A two cylinder internal combustion engine with the cylinders arranged on opposite sides of the crankshaft. The best known example is the ‘traditional’ (since 1923) BMW motorcycle engine, where it is known as the Boxer. Also known as Horizontally Opposed.
Used to describe the agility of a motorcycle, or how quickly a rider can “flick” the bike from side to side in turns.
The fuel reservoir on a carburettor into which fuel flow is controlled by a valve operated by a float.
The U.S. Department of Transportation’s Federal Motor Vehicle Safety Standard No. 218. It outlines the minimum standard requirements for all motorcycle helmets. Manufacturers must submit their helmets for compliance testing.
A flat-twin engine mounted with cylinders positioned in line with the frame.
Early three-wheeled vehicle with two-front wheels fitted to a motorcycle based fame. Passenger accommodation was sited above the front axle.
The metal tubes that connect the front wheel to the motorcycle frame via the triple tree. For handling, the front fork is a critical motorcycle component as it allows the rider to steer. The fork, along with its attachment points on the frame establish the critical motorcycle geometry parameters of rake and trail, which in turn contribute to wheelbase.
The most common engine design found in street motorcycles. It refers to the number of times a piston moves up and down through each power cycle.
- A downward stroke brings in the fuel/air mixture
- an upward stroke compresses the fuel/air mixture
- a downward stroke results when that mixture is ignited and expands (also known as the Power Stroke)
- and finally an upward stroke expels the exhaust gases
(Compare Two Stroke Engine)
Small, accessory motorcycle components designed to protect engine cases, bodywork, etc., in the event that the motorbike falls over. Frame sliders are like small knobs mounted to the engine or frame in such a way that they protrude beyond the bike’s body work, providing separation between a motorcycle’s expensive parts and the road surface in a fall. See Motorcycle Frame Sliders.
A device that serves the same function as a carburetor, but uses computer-controlled jets to inject atomized fuel and air into the air stream going into the engine. (See EFI).
