So, I am rebuilding one of my 2 banshees, this one for the last time. It has been almost 15 years since i last actively rode one. It would not start by kicking it, i could push start it. a compression check showed 110 in the right and 40 in the left. broken piston ring. It was already at 66mm bore. i was told it must be resleaved. i was able to have a shop bore it to 66.50 mm. the pistons the shop ordered were incorrect. They was 66.5 mm pistons, however they was for a stock crank and i have a 4mm stroker. All balls racing was able to provide a 66.50 stroker piston kit. now its time to re install the cool head from Pro Design. when i dissembled the cool head, it did have the factory metal head gasket as well as the O rings for a cool head. i am not sure if that was right or not but that is how it was. when i got the piston kit from all balls racing, it come with two metal head gaskets, a thin one like normal metal head gasket, and another one, much thicker, that had a tag saying only use this in plus 4 mm install. my question is do i need the metal head gaskets with a cool head install? does the cool head and its O rings install directly to the top of the jug without the metal head gasket? Thank you for any input