I have an 04 400i and I just installed an HMF for an 03 Rancher. With a little work and a homeade bracket it looks like it was made for the bike. It really helped the low end power and it really sounds good.
Thanks guys I appreciate it. I have been riding for a while but I have always had a stock machine. Now I am thinking about opening it up a little bit. Dont know much about ATV performance. Used to run a two stroke bike and had it about as hot as I could get it but dont know the right direction to go with the AC.