Have the tech working on your quad take the air filter housing off completely seal the intake end tape or rubber plug ect. smoke test it to see if you have a leak I have done this on several quads of mine to see if I have a clean side leak, I would recommend after rebuild going back to stock filter it filters better than foam but if you have a modified motor you will want the more air flow from a foam filter. I use a uni filter considerable difference on 2 of my Quads it lets more air in but also more dirt my other quad stock filter only clean side is always clean, I would stay away from a K&N. I ride in really dusty conditions. Just food for thought.