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Posted by: hobbyracer
i have an .80 over cylinder that keeps blowing head gaskets. i tried 3 different heads and still the same thing...runs great for about 20 min. i resurfaced the head and cylinder thinking that would help but no luck. it worked fine on another quad. anybody have this problem before.
Posted by: Fastestdad
Permatex copper coat spray. But it shouldnt blow em. Make sure your head gasket is ground/ fitted to the new bore size. Or head or cyl surface is not flat. Set the head on the cyl with no gasket and shine a light inside the bore you shouldnt see any light between head and cyl. You may see light between the head and cyl. To fix if it does. Take a piece of glass and put 600-1000 grit wet sandpaper on it with water and rub in a circular motion on the gasket surfaces you will smooth them out perfectly and will see as you go that one or the other wasnt completely flat cause you will see where you are taking aluminum off on the higher spots. When the whole gasket surface gets shiney it's flat and your head gasket will hold.
Posted by: billl2099
if the head and cylinder been resurface then i would guess it eaither over or under torque, do you know what the factory torque specs are and what order to tighten the bolts? also next time try useing a head gasket sealer, any parts store has that, just in case the milling on the head isn't perfect, that should fix the problem.
bill
