My sons' cr85 has overheated again. Last time it started steaming out the radiator overflow hose and he kept riding until it stopped running. I had a steel sleeve installed with an overbore that brought the cc's up to 96. It started steaming at practice on Sunday so we shut it down and tested for fuel in the coolant. I suspect the upper head gasket has failed. There is about five hours on the new cylinder. Does anyone know any special gasket or sealant combinations that I can use. I don't think there is a jetting issue as the plug looks good to me.