Motocross, Supercross, Arenacross, Freestyle Motocross, Supermoto
prefferably the 85cc class
85 cc or 150 cc
125 or 250 if you fit on the but but they run together in the 250 class
Once Motocross became popular, always outdoors, it migrated to stadiums which became Supercross, and for smaller stadiums or arenas, it became arena-cross, which are two different motocross venues. So you have, outdoor motocross, supercross, and arena cross.
there are many here are some: supercross arena cross motocross freestyle motocross indoor motocross outdoor motocross
250 C or Lites C would be the two beginner classes
Motocross, Supercross, Arenacross, Freestyle Motocross, Supermoto
motocross tracks
A cr250 is a motocross bike
yea but it's not a race bike it's a slow play bike
If you're good enough to run pro classes you can. Also if you can run consistently in the top in the pro classes, you can pick up some local sponsorship to help with the expense of your racing.