How much should I shave a Tri-Zinger head?

[thefox]

Lets say I have a YT60 tri-zinger with a fresh final bore, DG pipe, bigger carb. no air box, holeshot clutch springs and a blocked off oil pump. What should I shave the head but still be able to run it on pump gas?

[lndy650]

you have to find the compression ratio you want which for 93oct id say not much higher than 11:1 maybe 12. then figure out how many cc's the head has to be to get that ratio and keep cutting the head till you get it right. also when you cut a head you have to make sure you dont cut into the squish and the squish has to be at least .070 for 93 so sometimes you have to rechamber the head so you can cut it down far enough. .010-.020 would probably be acceptable with no rechambering nessesary.