文档介绍：Motorcycle engine
A motorcycle engine is an engine that powers a motorcycle.
Motorcycle engines may be two-stroke or four-stroke, reciprocating or Wankel, single-cylinder or multicylinder (if reciprocating), or single-rotor or twin-rotor (if Wankel). The engine typically drives the rear wheel, but some small bikes such as the Velosolex have a friction drive to the front wheel. Most engines have a gearbox of between two and six ratios, and the Honda Gold Wing touring motorcycle has a reverse gear. Power is sent to the driven wheel by belt, chain or shaft. In Europe, up till the 1970 Honda CB750, engine capacities typically ranged from about to ; but since then machines with capacities up to 2,300 cubic centimetres (140 cu in) Triumph Rocket 3 have mon. In the USA, motorcycles with large capacities have mon for much longer.
Even today, most motorcycles still bear some resemblance to early motorised bicycles, so the engine is normally found where the crank-wheel would be on a pedal bicycle. However, some early examples like the 1921 Megola and 1935 Killinger and Freund had the engine within the driven wheel, and the Velosolex has its engine ahead of the handlebars, just above the front wheel. Earliest motorcycle engine concept. This 1818 caricature was thought for many years to be entirely fanciful, until the Michaux-Perreaux, Roper and other steam cycles were rescued from obscurity, and the stories of the early steam cycle experiments were rediscovered. There were no steam motorcycles in 1818, but there soon would be.
Main article: Motorcycle history
The first motorcycles were powered by steam engines. The earliest example is the French Michaux-Perreaux steam velocipede of 1868. This was followed by the American Roper steam velocipede of 1869, and a number of other steam powered two and three wheelers, manufactured and sold to the public on through the early 20th century.[1]
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