Why do I need a filter?

Dirt from open air can cut an automobile's engine life down to 5,000 miles (or so). A motorcycle riding in the dust could wear out in as few as 500 miles without a filter (depends on dust conditions).

Paper Filter

Replace these. Some people use compressed air to blow the dirt off. Paper filters don't filter very well for an offroad machine that may get wet or may get a seriously clogged filter. See if you can get an aftermarket foam filter to fit your machine.

Foam Filter

A foam filter is best cleaned using a foam filter cleaner. Some people use a solvent, even gas. I would suggest going to the motorcycle store and getting spray filter cleaner and spray filter oil. I also use dish soap to clean the filter after using the spray cleaner (and rinsing). Do not drive your machine without applying filter oil to the foam filter. Follow instructions on the can.

K&N Filter

The offroad community commonly believes that Foam filters better than K&N. K&N filters tend to flow better than others. The best way to care for them is use K&N recharge kits and follow the instructions. They are very easy to clean and recharge. K&N filters may not work well if watery mud flips onto them or if they do not seal to the airbox correctly (if air can leak around the base). However foam may be a better choice if there is a good chance that mud will enter the airbox and get the filter soggy.