i just recently got my top end rebuilt with bore,port,pistons,and head mill and the base gaskets they gave me were oem yamaha and they fit perfect but all the gaskets i see are made out of like paper with a sealer applied to them and these ones were thicker and kinda like a soft metal gasket that you could scratch with your finger nail..has anyone ever used them? i think there fine as there oem yamaha but i dont wanna screw anything up when i go to fire it up. thanks