outerwears does not stop dust. It keeps large debris from getting stuck in the pleats and blocking up the filter faster. The problem with the K&N isn't the large stuff anyway on the blaster, it's the really small stuff. Personally, I run dual stage foam filters (UNI style if not UNI brand) and have been very pleased.... I would clean the UNI very well, oil it, slap it on, check the jetting, and roll on!