So in 2006 i bought my 400 for trail riding and to push snow. I went with the Arctic Cat because of the heavy platform,racks,bars,suspention ect. If only i new about the sluggish underpower part hungry motor. Rebuilt 3 times now and i consider my ridding as mild at best. Now i have a low idel random knock. It goes away when the rpm is raised and im thinking it could be the chain but it sounds like it comes from every where. Hard to trace by ear. Its always serviced at the dealer and im on a faily fresh top end rebuild. Help !!!!