Evolution 2 - Motocross - Sunday
Includes bikes with no linkage type rear suspension, no water cooling and no disc brakes. There are no travel limitations.
Evolution 3 - Motocross - Sunday
May have been produced with water cooling and have linkage type rear suspension, but cannot have disc brakes or any power valve type mechanism built directly into the engine. Yamaha's YZ 1982-1984 are the only eligible motorcycles allowed to use a power valve mechanism.
Revolution 1 - Motocross - Sunday
Includes motorcycles originally sold as 1998 and older (no like design) models.
Revolution 2 - Motocross - Sunday
Includes Motorcycles originally sold as 2008 and older (no like design) models. Two-stroke machines only.