Economical: never change another filter! Once you replace the standard air filter with the K&N permanent air filter, it will last as long as your bike. The standard carburettor and air filter housing configurations remain the same. Registration of the modification in the vehicle document is not necessary. Sporty: the K&N permanent air filter boosts power as better airflow means fuel and air is mixed more quickly. The engine responds more spontaneously when the throttle is opened and the faster filling of the cylinders is translated into better acceleration. K&N permanent air filters get the most out of your engine.