i believe you could run the dirt bike in colorado class if you wanted to just get a feel for the whole racing thing. the ninja 250 would probably be too slow to ever be competitive in any class. i would say look for an rs125 or tz125 if are into gp bikes or find a used sv. i do believe there is a pretty good deal on one over in the classified. the seller is ray-ray. if you want, you could drop me a pm with your phone # and we could talk in more detail
marty