bigger pistons or not
 

i am planning on rebuilding my engine and was wondering if i should get 81.25mm or stay with the stock size of 81mm and if i chose to go bigger what would i need to do to make it work and how much of an increase of power would it be if any? thanks

The only reason to go with larger pistons would be if you had to overbore the cylinders .25 over to eliminate out of round cylinder bores, deep scratches, incorrect piston-wall clearances, etc.

There would be no noticable increase in power. You might pick up a ft/lb or two, but nothing you should be able to feel.

thanks for the info schmoo, also with going with new same size pistons would it be nessasary to resleeve?

Check the bore and piston to wall clearance before doing anything. If it checks out, the bore should just be honed and a new set of piston rings installed. If not, you will have to overbore .25, but the sleeves will be fine.