Motocross — Such bikes (
once called "scramblers") are raced on short, closed off-road tracks with a variety of obstacles. The motorcycles have a small fuel tank for lightness and compactness. Long-travel suspension allows riders to take jumps at high speed.
Motocross engines are usually single-cylinder
two-stroke or
four-stroke units, which vary in size from 50cc up to about 650cc. Motocross sidecar outfits have bigger engines, usually four-stroke and often twin-cylinder. Motocross bikes are also used in
Freestyle Motocross.