Originally Posted by Bluethumb
I thought I've seen others w/ 800 cc motors, usually R80G/S's, upgrade by only swapping out the cylinders.
Usually those are Siebenrock kits. They make 1000cc pistons that match the combustion chamber of the 800cc heads. I'm not sure how much "better" that makes them, but they also have a higher 9.5:1 compression ratio.