air mixture screw and jet sizes - Snowmobile Forum: Your #1 Snowmobile Forum

paintexpt · 09-07-2008, 02:35 PM

Hello all, snow is coming, yea, I'm trying to get this air mixture and jet thing down, so a couple questions, on jets, the bigger the number the bigger the jet? or is it the other way around? on the air mixture screw, turning it out is more air, in is less air?
I have my 95 XLT lite 600 triple with slp pipes set for 3-6000 feet +10 to +40 degrees, using 210 jets and 1/2 turn out on the air mixture screw, does this sound correct?, as it is still 80 degrees I will have to wait a while to get to run it to check the plug color, last year just got to run it once and found it had 190 jets and it was boggy, from what I found 190 jets were 6-9000 feet, I am assuming that is why it was boggy as I was thinking it was not getting enough fuel, or am I wrong? Thanks Mike

BC_Dan · 09-08-2008, 01:00 AM

The bigger number, the bigger the jet is correct.

OUT on the air screw is more air (less fuel, means you are making it leaner)

IN on the air screw is less air (more fuel, means you are making it richer)

The pilot jet controls the fuel at idle up to about 1/8 throttle. Most of my Mikuni round slides worked pretty well at one turn out from lightly seated. Adjust the screw to get best (fastest) idle and make 'em both the same, you should be good to go.

When you were running the 190's, what color were your plugs? Going from 190 to 230 is a pretty healthy jump in fuel. (there goes your mpg...) Adding fuel can't hurt, jets are cheap if you go too big and have to reduce size some. I have found SLP to be pretty well dialed on their stuff, the jetting charts for their pipes are spot on from what I have experienced. All manufacturers have charts that are a little rich, to prevent lean burn-downs on those really cold mornings.

paintexpt · 09-08-2008, 09:35 AM

Thanks BC_Dan, I will adjust the air mixture like you said and will check my plug color on my first run, while Im at it, as I want to get all sleds up to par before winter, it sucks working on them in the cold, I dont run them too long as it is so hot out now, It dosnt hurt them to run on the trailer when hot outside does it? I will still need to make some adjustments in the winter as I live at 1100 ft and ride at 2500 and above, Im figuring the slp chart will have me running a little fat at 2500, but should run better as I climb

BC_Dan · 09-08-2008, 11:56 AM

If I run my sleds in the summer, I run 'em at least until the rear heat exchanger has warmed up to operating temp. A killer for sleds is starting them and running them just enough to develop a lot of condensation without the engine being hot enough to evaporate it out. The condensation can cause rust in the crank bearings, which is not so good for the crank.

I would watch the temp light, you don't want to run it to the point the light comes on. I find about 10 minutes at idle will warm up things nicely, and that gives me my 2-stroke smoke fix for the month

JheLrey · 09-08-2008, 01:53 PM

Wait for the evening when it gets cooler out... I've also when needed, will prop a garden hose with water running over my running boards. Mine are located directly under the footrest.

paintexpt · 09-09-2008, 09:17 AM

thanks guys, I did run it about 10 minutes , my neighbor got his 2 stroke smoke fix also,

haha