When i tryed to start my '01 banshee it backfired when i kicked it over, then on the next kick it started up. It reved real high on idle then went down to a low rev and then went back real high and then shut off. It was spitting a little bit of a dark oil out of both of the exhaust pipes, and recently it has been overheating a little it i ride it for a long period of time. So i figured it may be the spark plugs, when the took the left one out (when ur looking at the quad head on) a little bit of smoke came out of the piston hole where the spark plug was. Do i have a blown head gasket or a frozen piston or what?