Ok I am going to go buy jets today and I was wondering if anyone here from Utah could tell me what sizes to buy for this altitude. I am running the equivalent of an aftermarket end cap, a K&N, and I want to take the cover off my air box. I thought I read that most people buy anywhere from 160-180 to try. Excuse my ignorance as I am just getting started here. By the way, I am amazed at the quads I see on this site. I had no idea how fast and modified the DS can get.

 

What I did, was purchase one of each jet. 160-175, and put in what I guessed was as close I as could get and then we tried a couple different ones while we were riding. I could not guess for Utah, as the weather I am guessing is way different at your altitude then when I ride at the same elevation in our mountains. I am guessing that when I go to Little Sahara for DS Days I will be using 160-165 area. But I am guessing that is what I would be using....

 

If you have not yet read OMR's stock carb mods, you should do a search for "stock carb mods". And leave the lid on, it is just like the Old man said, the topend falls off big time! The mods are easy to do and well worth the effort.

 

Old man racing carb mods

 

I have a K&N and a HMF slip-on and live up in northern Utah, the only good ride I have been on since I installed both (damn long cold northern utah winters)was at Little Sahara at X-mas time. Temp was around 50-60 degrees and I was running with a 167.5 jet and the needle in 4th clip position, and lid on. It really ran great, if I wasn't having such a great time I would have stopped long enough to try a 170, plugs looked good and never a hesitation or sputter.