JESPOKER4FUN wrote on 02/26/10 at 18:03:13:Ok, I have been giving this some thought.
Lots of posts say to modify the spacer on the jet needle. (reduce the thickness)
I am guessing this is supposed to make it run richer, correct?
Well the problem I saw when I shaved down the spacer is that the needle position will not change due to the fact that the hole in the hold down plate is not large enough to allow the needle to pass through it and move upwards. I think I will have to drill the hole bigger in the hold down plate.
Please correct me if I am wrong about this.
Well, it works like this - in the good old days of about 1986 or 87 these needles had 3 slots where the c-clip goes - stock was in the center and if you needed the a richer fuel pattern you would lower the c-clip to the 3rd slot which would make the needle shorter , if you needed a leaner fuel pattern you would raise the c-clip to the 1st slot longer.
The length and taper of the needle control the fuel pattern through the needle jet tube - the tube is what needle fits into and at the bottom of the needle tube is where the main jet lives.
If you have a shorter needle it opens the needle jet sooner/faster than a longer needle - as the needle is lifted out of the needle jet tube as the slide goes up.
In the case of the white spacer being made thiner we are doing is the same thing as moving the c-clip down about a half of a notch.
Make sense?