Stewart, I have just finished reading the "need help with kx560" thread.
In regards to that engine, what if you made your own sleeve with reset exhaust and transfer heights to achieve optimum blow-down pressure, do you think that then it could make more power than your current 86*86 combo?
surely a properly thought out 91*91 combo (for example) would have to make more power than a 86*86, provided that everything else was optimised to match, such as exhaust pipe, cylinder head, ignition curve etc..
i have been doing a bit of searching on here and found alot of people talking about "short circuiting", when the piston uncovers the exhaust port at TDC. does a stock KX500 do this? if not, how much room is there to play? is a +5 stroker with no spacer, stock rod and piston going to uncover the ex port at TDC?
of course we are going to find all this out when my buddies stroker crank arrives and he tears the motor down, but like i said to you in my email, im trying to stay one step ahead and get some calcs done asap!
thanks, mark