HI EVERYONE I HAVE GOT A THUMPSTAR PITBIKE WHICH HAS 2 PROBLEMS 1ST IS NOT RUNNING 100% AND THE SECOND WEN I REV THE BIKE IT KEEPS BACKFIRING !! I THINK IT IS SOMTHING TO DO WITH FUEL MIXTURE COZ I CLEAN THE SPARK PLUG PUT IT BACK IN THE BIKE STARTS IT UP THEN TAKE PLUG BACK OUT AND ITS BLACK AND SOOTY!! HOPE SOMONE CAN HELP?
