I have a 400 Big Bear that I put a K&N filter on last year. When I purchased the filter it said no jetting required. I think this is when it became a little harder to keep running at idle. I have tried to set the carb settings and have removed the carb and cleaned it. It runs fine if I keep revved up or put it in gear and go. I'm thinking it may need a larger pilot jet in it.

Has anyone else run across this same problem? I am located in north Texas for elevation. I have also seen the quad was sold from a north Texas dealer as far as jetting when sold.