Ive herd nothing but good things about the K&N airfilters for atvs but recently my buddy had to have his engine rebulit. He had to get new valves put in. He says that they told him they were ruined because of the K&N airfilter. He said it lets to much air in or something. I was looking into buying one for my raptor but i dont want to get one if it destroys valves. Has anyone elese had this problem or is this just a bunch of bull?

 

you will be fine as long as you get the pre filter for it, the reason it got wrecked was because the k and n filter lets dust get through and it gets in your engine and wrecks it, you should be fine as long as you get the pre filter.

 

A properly maintained K&N will filter dirt just fine under normal conditions. But if you ride in a really dusty are, I would probably switch to Uni.

The K&N filter on my mini is right behind the front left tire and the engine was clean as could be when I installed a cylinder kit. So I know 1st hand they work in sand, even when getting sprayed regularly.

 

well he could have been letting too much air in, and didnt re-jet? If the exhaust was stock, there shouldnt have beend a problem though. If it ran lean the valves might have gotten hot and warped.