K&N by itself replacing the stock filter is NOT a good idea and will allow fine particles through.K&N's will ruin your machine in dusty conditions.
I also have an Outerwear cover on the K&N filter.K&N by itself replacing the stock filter is NOT a good idea and will allow fine particles through.
However, a K&N used as a pre-filter (like @Rabbit did) with the stock filter still in place is just fine. The K&N will catch 95% of the dust and the stock filter to do what it does best, stop the finest of particles. It will prolong the stock filter life 10-20 times, maybe even more.
Should have clarified. Had a 2012 Polaris 900 XP and a “friend” changed the OEM filter to a fast flow K&N filter. Dusted the engine. On the box the K&N filter was a use warning that “off road use will void all warranties”. Did not use the K&N on my Honda. Traded the Polaris for the Honda. You are right! It was the wrong filter to use on the Polaris.
That's how I also roll. Good set up.I’m running a Uni 3” foam pre-filter on the intake tube into the airbox and currently a K&N main filter. I checked the filter after 760 miles and the K&N, the airbox, and the outside of the Uni were all clean. I just have to clean the inside of the Uni. I am satisfied with this arrangement for it’s return on the investment. I now have 4 Uni filters to swap out as needed on the fly.