batman wrote on 09/10/19 at 07:49:40:Dave, Each stage of the throttle opening controls the speed of the motor ,but nothing stops the pilot jet from flowing even at WOT ,it may feed less fuel over all, due to the drop in vacuum as the throttle plate opens , but there's never a time that the vacuum drops to zero , nor is there a controlling devise that would close the circuit, like that found in the TEV valve .
Batman: I don't agree.......once the throttle plate (butterfly) moves away from the idle ports, the vacuum is not concentrated at the ports and there is not sufficient vacuum to pull the fuel/air mix out of the pilot circuit.
I realize this explanation is not a CV motorcycle carb - however the relationship of the butterfly and idle circuit works the same.
http://leakylugnut.com/fuel-management/carburetors/Even if some fuel/air does trickle out of the pilot circuit at more than 1/4 throttle......it is such a tiny amount it doesn't make a crappity smack bit of difference!!!!!!!! Trying to adjust the idle fuel screw to change how the bike runs at 70-80 mph is a waste of time.