Relation between pilot jet and air screw
 

What is the difference between,for example,42* pilot and as 2 out and 40 and as 1 out?*



In my case with N8RH needle. On exc 250 2t 2011

I did some playing with this, and from memory the AS only really has a small scope at which it is effective, where on a needle with a long straight section the diameter plays a bigger part.

I found being too rich on the diameter a better option than being too lean.