just bought a fmf exhaust that came from polaris do i need a fuel controller for it or does the fact that it came from polaris make it ok.saw one post that said his was runing to lean and that the mufler was geting so hot it was melting the plastic.will this happen to mine.also does anybody know if the fmf muffler has to be repacked like the 2 brothers one and if so how often.thank you for your time and have a nice day.

Is the exhaust a slip on muffler or is it a full exhaust with head pipe from engine back?? You shouldnt need a fuel controller if its just the slip on exhaust, but if its a full exhaust system you probably will need the fuel controller, but its hard to say...it depends a lot on what temperatures and elevations you ride at. I'm not sure if your pipe will need to be repacked, depends on what model of fmf you have. If it is a muffler thats needs to be repacked in time, you will know when it needs it bc it will get noticeably louder, but that wouldnt be for quite a few hours til that would have to be done anyway.

its the Powerline
POL RANGER 800 RZR'07 POWERLINE MFLR.and i live in texas but might ocasionaly go up to the mountains in utah why does altitude make a difference on a fuel injected vehicle,i thought they adjusted themselves,although i do understand that there will be less power

technically the elevation shouldnt make a difference in an EFI vehicle but I have heard of a few instances where it did. If you just installed the powerline muffler you shouldnt need a fuel controller because the head pipes are still factory specs. As far as the packing in the muffler, I am not sure if that model muffler is packed or not, but if I were you, I really wouldnt worry about that until it gets noticeably louder if it ever does. I had a white bros. exhaust on my 400ex for 3 years and never needed to repack it...and I rode it on average of 20-30 hrs per month for 3 years straight.