MXA TEAM TESTED: K&N HONDA CRF450 X-STREAM XD AIR FILTER

WHAT IS IT? Air filters have not been one of Honda’s strong suits over the last two decades. The tight confines of aluminum Delta-box frames don’t exactly offer friendly ingress and egress for foam air filters. This is where K&N’s molded, rubber-framed, washable, HA-4513XD fabric air filter comes into play. The “XD” indicates an extra-fine weave for added protection against dirt.

CONTACT? www.knfilters.com or (800) 858-3333.

WHAT’S IT COST? $85.00.

WHAT STANDS OUT? Here’s a list of things that stand out with K&N’s CRF450 air filter.

(1) Installation. Step one: remove the stock air filter and cage—you won’t be needing them. Step two: since the K&N X-Stream filter comes in two pieces, you install the K&N filter first, minus the top piece. Thanks to the K&N filter’s rubber construction, you can squeeze it to help it fit through the frame. Step three: put the supplied rubber washer on the center of the K&N’s top piece and slide the stock wing-nut bolt through the washer and the top. Step four: line the wing-nut bolt up with the stock airbox post before snapping the top into place. Do not overtighten the wing-nut bolt, and make sure to apply the included grease.

(2) Oiling. Out of the box, the K&N filter is pre-oiled, but the black polyurethane sealing surface needs to be greased to help it stay secure. K&N provides a tube of sealing grease with every filter.

(3) Cleaning. One of the best traits of a K&N X-Stream filter is that it doesn’t need to be cleaned as often as a foam filter because of its larger, pleated surface area. When it does need maintenance, you can use K&N’s filter care kit that includes cleaner and air-filter oil. You just spray the filter cleaner on the fabric and back-flush the dirt out with cool water. Once the filter dries, you can manually apply the K&N filter oil to the pleats or use K&N’s aerosol air-filter oil.

(4) Construction. A fabric filter is an entirely different animal from the typical foam air filter. Instead of oil-soaked reticulated foam, a fabric filter uses fine strands of oil-soaked cotton material sandwiched between two layers of wire screen. The filter’s surface area is increased by the pleated design.

(5) Performance. Once in motion, the MXA test riders could feel a slight increase in throttle response, but no rider raved about an overall increase in power. On the dyno, the minimal air restriction of the K&N air filter made a little more power everywhere on the curve (but never as much horsepower).

WHAT’S THE SQUAWK? Price. At $85, it is expensive. It comes with a one-year warranty and, when treated properly, should last longer than a foam air filter.