The dense material the K&N filter is made with adds a lot of restriction. Oiling the media as they suggest makes it even more likely to hinder the flow. The K&N filter on my Harley Soft Tail got so clogged the bike wouldn't run more than 40 MPH, and washing it in solvent didn't help. I discarded it and switched to a paper filter. and performance and fuel economy increased dramatically. A pleated paper filter at a fraction of the cost does not restrict airflow nearly as much, and it can be discarded when it gets dirty. K&N uses the "P.T. Barnum" business model, and lots of people fall victim to their advertising claims.
Jerry
