Well I am real new to two strokes. I had my Yz for about three or so months and I am still fouling spark plugs. I ride in trails and sand pits, when they foul I am usally in a tight spot where I just hold in the clutch and manuver myself out of it. (IE:Rocky parts on trails). Is this because I'm not revving it up? Thanks just let me know if you need specs of my motor, its somewhat worked.