Scooterotica

Please could someone tell me that when you look for a piston you get std,++,+ ,or _ , and i`m only looking for
66mm one for the 2 barrels i have acquired.they were of scooter restoration site

The barrel is usually graded and stamped with an indicator 0, +, ++ etc. But that is only valid if you're sure they're new and not re bored or honed.

Thanks very much for that Rosscla