I'm installing a HMF utility muffler today. will it hurt anthing if I don't rejet just add the muffler

 

Like I said yesterday, I would reccomend rejetting and adding the air filter at the same time. I doubt it would hurt to just add the pipe. You may need to adjust your air/fuel screw a little, but probably not. Put her on and let it rip, see how your quad reacts and go from there. Remember your not going to notice much of a gain with just the slip on. Get your filter and buy the inexpensive jets ( recommend 3 different sizes each being bigger then the other) and put it in. Its not hard.

 

on my warrior.. i put the sport series slip on on and i did not have to rejet. Just had to adjust the air/fuel screw all the way in and then 2 and a half screws out.