Review on K&N Engine Air Filter YA-6602: High Performance Premium Powersport Air Filter for 2002-2013 YAMAHA YFM350R Raptor, YFM660 Grizzly Auto 4x4, YFM660 Grizzly (Black) by Brian Barnes

The instructions are clear. Fits great. The price is too high. American way. Truth. The filter attaches with a pressure fitting to the slot under the main air intake and to the rib on the back of the air filter housing. The default filter uses the same setting. A lot of people here complain that they don't fit well. If your filter box has warped, melted or something like that, you're right, the fit will be wobbly. Mine went in fine. Follow the instructions and use seal grease. I'm so damn glad I don't use that stupid oily foam anymore, I can't see clearly anymore. Having a filter that can be washed with water is awesome. I replaced the foam filters with every oil change because they are so poorly made that they tear and the seams fail. K&N has not disappointed me yet. There are tests that show K&N lets slightly larger particles through than paper or oil filters, but compare this to the particle size of exhaust gases. Guess what? Practically no difference. So it's really up to you to debate whether these filters are safe for your engine, but as far as I'm concerned one of these has been on my truck for 13 years and has worked consistently. I'm happy with that.