hi scott,yes i was the fool who bought the huge jigsaw that zanx called a kx500(he promised every part was there as i loaded a frame and 8 huge boxes of bits into my van,and he did,nt let me down).i tracked down the engineer who worked out the pro,s of a cr500 rod,matched to a +40 piston.the guy wrote down the final formula i guess you would call it,and i have also spoken to another guy who still races a kx580 for a bit of cheap fun,he says its best trick is leaving honda cr500,s in his dust,followed by the cr riders scratching their heads whilst looking over his bike trying to work out how he can be so quick,i nearly gave up on this project 2 months ago but zanx talked me out of it ,and im so glad he did,cos now its in supermoto form,i think its the sexiest thing going (too many late nights working on her has left its mark)