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Needle Jet Adjustment Question


Richer

I went richer on the mains all the way to 142.5's in steps testing top end each step and noticed little if any difference in speed. I also had the needles raised i setting rich. The theory was that it would be faster at raising the needle 1 and using the 137.5's I didn't find that true one way or the other. I will tell you that over 40 degrees F It ran like #*$&@ with the richer settings. So I am thinking unless you are doing your riding below 0 consistently there is no point to going richer and if you do you will sacrifice some fuel economy.
 
Brx, Most of my riding is between -10 and -30 celcius, the milage would decrease under warmer temps, however with the inclusion of the pipe and home made cold air kit im getting more air flow therefore resulting in the need for more fuel, thats likly the reason for my increase in mileage, Isorry for not explaining it better :)
 
I think the key thing here is to differentiate between those of us STOCK and those of us MODIFIED. I am completely STOCK meaning that I have not modified my airbox or anything else on the motor. If you have modded the airbox to give you more AIR then naturally you will need more fuel!

Here is what I will be doing....trying the NEEDLEs as they are now (1 position leaner) with Stock Main's (135's)

Then mid-way through the season I will try the same needle setting with 137.5 Mains

If there is no noticeable difference I will switch back to STOCK!

In theory I have learned alot about this machine BUT...I'm not one to tinker too much.. :oops: ..I have gotten myself into trouble in the past with other sleds so riding a FULL season without any problems is first and foremost. Nothing is worse than missing a trip with the boys because your ride is down..TRUST ME!
 
Hi rxwonder,i would leave stock jets in i went to 137.5 but most of time its to rich for stock sled unless you are at -30 and running wfo now droping needle will clean up part throttle riding,better milage,on a 2- stroke must be careful as you can cause a lean spot in a certain area and burn down,on the 4- stroke it seems ok in small increments and will pull better milage,but has no affect on top end,when slides are fully opened,they are not working,they are to far out of the jet tube,maine jet only working now,good luck.
 
So is leaning the needles one click #2 or #4 on the needle, I can't remember but I'd guess #2. I have 132.5 mains in my mountain Rx-1 that's supposedly good for zero degrees at 1,700 to 6,700 feet.
It's the shits there is no needle position change in the books from sea level to 11,000 feet. I think there should be so we don't have to play guinee pig (not that we wouldn't anyway). Powder Blue
 
Needle Position

PB it could only help you to raise the clip(lower the needle) since you ride at altitude. If we can due it at 500', you would surely benefit. Just rmember to not lose those tiny O- Rings when you pull the covers off.
 
Ok, I'll try a full clip position. I was going to go 1/2 of a click but since you guys can do it down low a full drop to the #2 position should make me not have to carry gas in the mountains.
I shouldn't have to raise my mains a notch to do this, should I? PB
 
Does these carbs have the washers to only change half a needle position?
I didn't think they had them!

SEND HELP!!! I HAVEN'T HAD THESE CARBS APART, YET!!!!!!!!!!!!!!!!!!

THANKS GUYS!

BR
 
It's the little white washers that give you the "1/2 positions".
One thin washer above and one below the clip give you the 1/2 positions.

So in the center slot in the clip (the #3 positon) if you have one of the little white washers above and one below you really aren't in the #3 needle positon it actually the 2.5 position. To atain the #3 position you need both white plastic washers UNDER the clip.

So, you could lean your needles in 1/2 position increments. To go 1/2 a position leaner than #3 you would go to the slot 4th from the top on the needle and have one washer above and one below the clip. For a full position adjustment you'd have both washers under the clip in the 4th slot from the top or the #4 positon. Then you are one full notch leaner on the needles.
The same theory applies in going richer. I hope this helps. It's a lot easier to explain with a picture. if some one has the Yamaha technical update manual on CD maybe they can post a picture. I'm on page 1-112 as I post this info. PB
 
GOOD POWDER BLUE,

Thats what I'll do then is go 1/2 leaner not a full clip!

I was told last year they didn't have these washers for that adjustment on these carbs!

THANKS

BR
 
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