Yesterday, 11:58 AM
FWIW the last time I had to get a SU set up on a rolling road, with a SU specialist, he started with a weak needle and tuned it in by filing a flat along one side progressively working from idle. He got an ideal result and I never had any mixture problems thereafter. This was done after he had set up the piston to rise to near maximum at max depression. This can be done either by adjusting piston weight or spring strength if carb has one.