i dont think your understanding what im typing
i bought the quad from a guy, who said he had it bored to 64.5. on the stock head. i had to repair the kickstart gear because a bushing wore out and was able to tell then that the motor was complete appart for the rebuild
while riding it, the headgasket blew, i could tell due to antifreeze leaking into the cylinder and outside the head.
I pulled the head to replace the headgasket, and found that the reason why the previous owner bored it to 64.5 was due to him blowing it up to the point that stuff hit the head, chipping it all up. He just cleaned the head up and reused it.
Well looking closer, i was able to see a big scar in the cylinder, which had to of occured when he blew it up, because i could tell it was honed, and the pistons were in great shape, just some carbon buildup.
knowing the scar would kill my compression due to blow by, i got a set of freshly bored cylinders that are 65mm, and 2 brand new pistons for it. i also got a cool head to fix the chipped up head issue,
i know that everything that i did is top notch, not my first rodeo building 2 stokes, i just wanted to know if it was going to knock me way out of wack for jetting.