From:Backyard Bob e-mail:somewhere-A- new jersey
Subject:RE: Need help with piston! Date:Thu May 23 23:53:25 2013
Response to:18503
It's my understanding the factory offered .010", .020" & .030" oversize pistons. The aftermarket companies (like Hepolite) offered .040" & .050" pistons for the brave of heart. If you're running a race engine I'd overbore and add a few thousands of an inch over suggested clearance to avoid seizer. I'd check with Mutt on his recommendations.

Hello all, I am in need of some help finding a new piston / rings for my 1956 ST165. I have been told the standard piston for this bike is 2.375. The old piston out of my bike measures 2.400, with a bore of 2.403. So I am assuming my cylinder has been bored 0.025. Well, I canít find a 0.025 over sized piston, anywhere. Harley has over sized pistons in 0.020 increments, which is no help to me. Anyone know where I can find a 0.025 over piston w/rings? Need ASAP because Iím racing at Wauseon in 8 weeks. Please email me as well as replying here so Iím sure to get it. Thanks.