I just bought a Bowman Ring formy RCGF 26. When Mr Bowman sent the ring to me he also inculded anote that said the Reed Valve in these Chinese engines and he did say all of them. Sometime comes with mold flashing that needs clean up.. You remove the plastic reed valve and you can see where the plastic mold marks need sanded to achieve a good seal. It doesn't happen on all of them, but a good idea to check them all, it does happen to often and it lets them suck air between the gasket andthe reed valve