Thumper (motorcycle)

A motorcycle engine is an engine that powers a motorcycle.

Motorcycle engines are typically two-stroke or four-stroke internal combustion engines, but other engine types (such as Wankels and electric motors) have been used in small numbers. Although some mopeds had friction drive to the front tyre, a motorcycle engine invariably drives the rear wheel, power being sent to the driven wheel by belt, chain or shaft . Most engines have a gearbox with up to six ratios. Reverse gear is occasionally found on heavy tourers and sidecar motorcycles. Gear changes are normally effected using a foot-pedal and manual clutch, but early models had hand-levers. Some bikes have automatic or semi-automatic gearboxes.

Outside the United States, engine capacities typically ranged from about 50 cc to 650 cc; but in Europe since 1968 motorcycles with larger capacities have become common. In the United States, V-twin engined-motorcycles with capacities of 850 cc or more have been the norm since the 1920s.

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.

Using frames based both on the earlier boneshaker and the later—and in many ways completely modern—safety bicycle design, these early steam motorcycles experimented with a variety of engine placement strategies, as well as transmission and options. While today nearly every motorcycle has its engine in the center of the frame; this became standard only around 1900-1910 after nearly every possible engine location was tried. The origins of the scooter engine arrangement (including the shaft drive) can be traced back to the 19th century but the current layout became generally adopted after the Great War. The modern equivalent became universally popular in the 1950s and remains much the same today.

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Wikipedia