Originally Posted by vincent713
I would definitely change out the jug, it looks damaged enough to lose compression. These engines have very limited horse power and you certainly don't want anything to rob from it. I would check online and see how much it would cost for the top kit with piston & rings and see if it's feasible to replace vs. ordering a bare bone engine.
Top end kit for 66cc is about $60 before shipping, $74 shipped to my location (from Gasbike.net). BGF on ebay has it listed for $37 with free delivery, and the BGF motor only seems to be selling at $98 delivered....