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I had my bike jetted for about 80 degrees. I believe i was running stock jets for the 220. I think thats a 145 main and a 42 pilot. Now the temps are about 50-60. Should i move up to a 150 main? Or a 152? And as far as the pilot i was thinking a 48? Thanks for any advice. It is getting colder and the temps here will drop to about 30's so i can go a little rich, but i know i most likely will have to jet again.

Let your WOT plug chop be your guide on the main. As for the pilot, look at what CC had to say in thread 3121 Experiencing some bog problems.

I can run my 40 pilot all year in temps from 35-85, but I have the amazing RB carb, which can run underwater, in zero gravity, and through gay whale tree hugging hemp smoking camp sites. I do change the needle though.

just took out the main, it is only a 140. Should i buy a 145 and a 148? As for my pilot should i try a 48? and maybe a 45? it would not hurt to run rich, i just dont want to go lean.

Going from a 42 to a 45 pilot is significant, going to a 48 is a huge change that might be good for Fairbanks in January. Just do as CC described.

i cant find his post, could i have the link? thanks. I think i will try a 148 main and a 45 pilot if they have 1.

Bradf wrote ..."gay whale tree hugging hemp smoking camp sites" ROFLMAF

i think maybe i will try and adjust my needle cause its free! and i will buy a 145 and a 148 main, and if they have a 45 pilot i will think about it. Thanks for all your help. I will let you all know how it runs tommorow.

FYI, getting gas in your eye when taking off the fuel line REALLY burns.

i ended up getting a 45 and 48 pilot and a 145 main. The guy at the shop told me to try just putting in the 45 pilot and keeping my 140 main in the bike. I will post results tommorow after a ride.

Ryan wrote:i ended up getting a 45 and 48 pilot and a 145 main. The guy at the shop told me to try just putting in the 45 pilot and keeping my 140 main in the bike. I will post results tommorow after a ride.

I'm not sure I'd trust "the guy" at the shop that told you to change just your pilot jet to account for cooler temps. Maybe he's looking for some work?

Inda has the JD jetting guide somewhere on this site. Good info. Using it, you will find that:

Given everything else is the same (altitude, relative humidity). A temperature change from 80 degrees to 50 degrees will net approx. a 5% leaner fuel mixture. Adjusting your pilot to a 45 will bring the mixture back up from closed throttle to 1/8th throttle. You will still be approx. 5% leaner from 1/8th to full throttle. Is this what your trying to do?

Theoretically, if your jetting was spot on for 80 degrees, you should adjust your jetting across the board by 5% richer to have the same jetting. Unfortunalty, there is no 3.15 clip position in the needle, no 44.21 pilot and no 147.3684 main jet. Also, unfortunatley, bikes DO NOT react to jetting changes exactly as a jetting chart suggests they should.

Good luck.

maybe i will put the 145 main in then and see how it runs.

Follow these instructions to the letter.

http://justkdx.dirtrider.net/carbtuning.html

i put in the 45 pilot to see what it would do and it is still to rich. I then decided to take it out and try stock jets in the 55 degree weather. It ran better than i think it ever has. It only really smokes when i am full throttle. Other than that, almost no smoke. My friend friends came over today and one of them asked me if i wanted to race. I was curious how i would do since i have never done a real drag before so i said yes. He has a Bombardier DS650. This race was neck and neck the whole way with me ahead by about 5 or 6 feet the whole time. By the end though after the first 1000 feet he had me cause he tops at like 80. I was bumed but at least i know my bike is finally jetted dang close to being spot on.