I rebuilt my 2000 banshee and it ran fine for about 3 weeks and one day i was riding it and it started backfiring and sputtering and would only go about 5 mph. I had a air leak in one of my boots so i replaced them and it still does it. Both plugs were oil fouled so i replaced them and the new ones even had oil on them. I was running 20:1 the whole time. Does anyone have any advice? Should i run a different gas mixture? I have t5's, vforce reeds, ported cylinders, dyna ignition, aftermarket carbs. I am running 93 octane. NEED HELP