A little more on the low speed needle. I have always found my greatest gains in runtime are made by working with adjustment to the low speed needle. To me it is the hardest to get set right because it seems to have the widest tuning window. Depending on the idle gap setting it can be off quite a bit and still sound fairly good.

Most of the time just a little running will let you get the high speed close then it can be set correctly after the low speed is adjusted.

A good example is a dirt oval car I adjusted for another racer about a month ago. He was pleased with performance but getting less than 4 minutes per tank. Start adjusting on the low speed needle and idle with tweeks to the high speed and run times went to over 6 minutes, power was higher and temps were lower. It was rich on the bottom and the idle gap was covering it up. BTW, the high speed needle had to be richened because it was so fat on the bottom.

There can be a pretty good interaction between the needles at times.

And no, I don't claim to be good at tuning, but I'm a lot better than some that think they are.

Ed M.