I agree with what you guys are saying. I have ridden big bore since 1978 - the RM370, then 80 KX420, 82 IT465, 85 KX500, 88 KX500, 98 XR600, back to 03 KX500. Size of rider means less than control of the throttle and clutch. But big guys like me need a bike that can carry a load. I like the flywheel weight in tight stuff I spend a lot of time in 2nd and lugg into each gear at low rpms till the trail opens up then hit the pipe. Riding smaller bikes requires more rpms. Climbs like a billy goat. I followed stewart's mod suggestions KIPS bolt, windowed piston, Vforce reed, and gnarly pipe. I can't prove it but I'm sure I got 20% more hp. It's smooth all the way through.