I have a vinson 500 im currently working on, my buddy had this wheeler with me creek riding the other day. Buried the front end in water over handlebars, filled oil, cylinder, airbox, beltdrive, fuel tank with water. I cleaned the tank and fuel shut off valve, cleaned whole carburator, changed oil several times. It runs and idles now, but quickly after starting the exhaust gets really hot and seems to run lean (fumes burn eyes, smells of rotten eggs) and when you rev motor it cuts out badly and wont hardly do 20mph... any ideas? burnt piston, head gasket, ignition problems? please help...   Ryan