shortening the stroke of your crank will give you more RPMs but will reduce the ccs (not keen on that idea ). another Idea might be to lighten your piston and conrod . My yellow jacket piston is ported along these lines
http://groups.msn.com/BedfordVans/st...to&PhotoID=532and I think the skirt has been raised (I don't want too pull my motor apart just for a photo so I've drawn on the old one) lighter piston and conrod "may" change direction quicker therefore adding RPMs
PS. When you lighten the piston and conrod the closer they are to failing .lighten them to much and something will break
PPS. how many RPMs have you got Crash Dummy ? I've got about 10500 with only bolt on stuff .haven't checked the flywheel for balance yet
