the gasket is in there. I'm going to try running it again tomorrow, this time i cleaned the spark plug and when i run it, if it turns black in the short time I run it i'll tighten down the head more.How long did you ride it? If it wasn't long, it could've been oil or fluids that you accidently got onto the engine. OR did you forget to put a gasket or RTV on something that needed them? Happened to me on a recent valve adjustment I did. Oil leaked out onto exhaust and smoked like crazy. Little bit of RTV and problem solved.