Motorcycle

Motorcycle A two-wheeled motor vehicle resembling a heavy bicycle, sometimes having two saddles and a sidecar with a third wheel.motorcycle, motor vehicle whose design is based on the bicycle. The motorcycle did not become dependable and popular, however, until after 1900. The typical motorcycle has an air-cooled engine supported in a metal frame between two wheels. Sometimes a third wheel is added to support an open carriage, called a sidecar, which is attached to the motorcycle. The motor is a two- or four-cycle gasoline engine with one to four cylinders. Although the motorcycle is not as safe a vehicle as the automobile, its convenience and economy have made it very popular. It is widely used for pleasure riding, racing, and commercial transportation of light goods.