kx250 vs kdx200

i have a kx 250 and my buddy has a kdx 200 and for some reason his bike is faster than mine in low end and top end? his pipe is bigger than mine and i dunno whats the deal my kx is an 89 and his kdx is a 90 im going to check the sprokets tom. i have 2 leaner jets than stock on my kx and a signature series fmf pipe and his is bone stock and were at maybe 500ft elv. so whats the deal? we race all the time in dirt or on the pavement...
please help

no help dang

dirtrider.net sucks ****ing butthole