I'm one of those racers that switched from two to four stroke to stay competitive,
biggest mistake I ever made. Yes it was easier to lay down faster lap times and
fatigue didn't set in as early in the moto, but the tradeoff was a huge increase
in cost and a huge decrease in fun.
I wised up late in '06, sitting in a hospital bed (engine blew up again and seized
off the face of a double). Fortunately, I managed to sell all of my bikes and parts
to unsuspecting wanabes. It's back to two strokes only, from now on.
The way I see it, you have a few options. You can go with a 250 2T and spend
a large amount of money to get the power needed to race heads up with the 450s,
you can opt for a 285 or 300 and be more competetive without spending bags of
money or you can pick up a 500 AF and dominate the 450s.
I had over $17,000 tied up in the last CR I raced ('03). You can buy a brand new
YZ and a big bore kit, or a Katoom 300 for less than half that amount. Even a
Service Honda CR or KX 500 would cost much less than the amount required to
make a 250 2t competitive.
I plan to race my CR250 in the 250f class. Unlike the AMA, I believe everybody
should be equal.

dogger