Hmf has a sport slip on muffler that comes with jets for free. My question is do you have to re jet when putting a k@n airfilter on, or does the kit include jets as well for the k@n filter. The muffler and filter bought separatly because it is cheaper on ebay than buying direct. It is for a suzuki vinson 5 speed. Thanks Patrick

 

The jets that come with the kit will be fine, but call HMF and confirm with them. They are good people and will be happy to help.

 

You should be fine with the jets it comes with. The filter isn't going to make too much of a difference, but when in doubt go one size larger. Now if you do air box mod like a snorkle or open up the air intake you'll have to go larger than what comes with it.

 

The HMF Utility comes with a #142 Keihin main jet. I would also change the pilot jet to a # 38. These recommendations are for sea level. The better route would be to get a Dynojet kit and do the slide mod while you have the carb apart.

 

yes get the dynojet kit. I did this with my o4 vinson when I installed the hmf. jet and slide spring and it made it rev like a sport quad!

 

Path5604, you can get even more throttle response if you will drill the air passage in the slide with a 1/8" bit. No more slight bog off the start til engine vacuum pulls the slide up. I know the spring that Dynojet sends is better response than stock but with the added size of the air passage of the hole you drill it lets the air escape from the top of the slide quicker on acceleration. This mod will not affect jetting.