The Alloy gaskets are the go for the big bore kits. As for going 160 by stroking............bad move unless your going to fit 20mm longer rod,studs and spacer. We stroked a couple of motors doing R&D from standard 57mm out to 59-61.5 not anything I will be doing for a motor that needs to rev again in a hurry. Here's Why ................the crank angle gets all F*&^%d up and you end up dropping power in the higher rev range very rapidly because the piston is trying to push through the cylider wall 1/2 way through the stroke because of the massive angles rather than move up the cylinder. The only way is to increase the rod length (and studs and spacer at bottom of cyl and cam chain) as well to reduce these horrid angles. The stroked motors make great bottom end though but will hate to rev (this is from experience). Here is some food for thought.......why do the jap 450's only run 60-62mm strokes with 90+mm pistons............. 1 good reason, they get reliability from big pistons. Yeah its hard work to get bigger than 59mm into the china's but were working on it.......... Try to find some guys that actually have worked on these things and failures and success they will have some idea what there doing. Then see if they will give you any advice. It can save you time and money not to mention some hard work.
