Bikes gradually evolved until 1958 when the first four-cylinder motorcycle was made. Many people were going away from the classic look and buying Asian bike like Kawasaki, Honda, Suzuki, and then later Yamaha. These bikes had a noticeably higher sound because they ran at higher rpm s. These bikes also generally went faster. They soon took over the racing market.
Today there are many different kinds of motorcycle racing.
One of the most popular forms of motorcycle racing is motocross. In motocross you use dirtbikes. The two classes of motocross are 125cc and 250cc. Usually the 250cc races are more exciting to watch because of the faster speeds and larger jumps. Motocross is done on a dirt track.