July 10, 200818 yr Hi folks, I've heard SOOOO many conflicting stories on what piston to use for a small big bore (145cc ish) TL 125. Some say CB750 some say CB500 some say Sammy Miller.................. Any one have any REAL experience on this?
July 10, 200818 yr I have installed a number of those big bore kits. The piston is the standard (not oversize) one from the Honda CB750 single overhead cam (2 valve) engines made from 1969 onwards. The problem is that the compression with that piston is huge. You must use a Sammy Miller head gasket , which is really thick, or use a stack of base gaskets. This increase in cylinder height may also mean you need to use an old cam chain rather than put on the new one at the same time. The Sammy kit is probably easiest in the long run. Note: this mod is only for the old 125 motors with 122cc cast into the base of the barrel
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.