Needle clip?

[stocktires]

What exactly does the needle clip position do? I know the air screw controls the very bottom, needle controls most of the lower end carburetion and the main controls about 3/4 throttle and up. The position makes the needle sit lower or higher above the main jet, right? Which I'm taking a big gues that it may change the point at which the main jet comes into play?

[ZRider400]

needle is for 1/2- 3/4 throttle.

lowering the needle(raising clip) leans it out.... raising it richens it.(lowering clip)

[velocityatv]

If you ever have questions about settings or what parts do what on a carb look at this page nacs racing atv spec sheet

it controls 1/4 to 3/4 throttle

with certain port jobs and pipes the right needle or wrong needle can make the biggest difference

I went from a dgh needle to a cel needle and i picked up a HUGE amount of mid throttle power. I seemed to always foul plugs in my midrange because it would slightly bog, changing the needle helped tremendously.

My buddies didnt think it would do much but when i switched the needle and they rode my bike they were believers as well

[ZRider400]

Originally posted by BeeeRock!
it controls 1/4 to 3/4 throttle

with certain port jobs and pipes the right needle or wrong needle can make the biggest difference

I went from a dgh needle to a cel needle and i picked up a HUGE amount of mid throttle power. I seemed to always foul plugs in my midrange because it would slightly bog, changing the needle helped tremendously.

My buddies didnt think it would do much but when i switched the needle and they rode my bike they were believers as well

what carb do you run? i always had problem with my old R in the midrange and never tried changing the needle..... i should have though.

[wilkin250r]

In a nutshell, the needle controls your mixture in the middle-throttle range.

Your needle is tapered, right? It starts off thick at the top, then gets thinner as it goes down. This way, the needles acts as sort of a "plug" for the jetting.

So, think about it. The fuel comes up from the float bowl through the main jet and past the needle. When the needle is sitting real low, the fat section is blocking most of the whole, so not much fuel gets through. Well this works, since this is also at low throttle, so you don't WANT very much fuel, because you're not getting very much air.

Now, raise the throttle, which also raises the needle. Now the skinny part is in the hole, which allows more fuel to get through. Perfect, because you need more fuel now that the throttle is open and you're getting more air. This is how your needle works.

Now, imagine in your mind, the throttle is half way open (or half closed, if you're a pessimist). Freeze the throttle in this position, and imagine moving the clip. Moving the clip UP will make the needle go DOWN. Down means the fatter section is blocking the fuel passage, so you get less fuel, leaning out your mixture at this throttle position. Moving the clip DOWN will make the needle come up, which results in more fuel.

This is how you adjust your mixture between 1/4 and 3/4 throttle.

Originally posted by ZRider400
what carb do you run? i always had problem with my old R in the midrange and never tried changing the needle..... i should have though.

im running a pwk 39mm keihn

[ZRider400]

Originally posted by BeeeRock!
im running a pwk 39mm keihn

cool thats the same thing i had on my old R