Modern Vespa

I was fiddling with my A/F mixture on a keihin CV... I was having fun with my presets when I changed it like a noob. Now I'm back to 2 turn out... in the beginning at 20 the scooter was picking up easily all the way to 55mph.. after I change the screw.. the scooter was picking up at 30..35 .. does he pick up later because of too much gas or not enough that is the question..?

Peace guys

That A/F mixture screw is only relevant at idle. Adjust in tandem with the idle stop screw to produce the lowest smooth idle revs.

Pretty sure I get different pick up at low speed with different "settings".. maybe in my head...

Thanks

The air/fuel screw doesn't have one position that works on all scooters. That is why you need to adjust it when the engine is really warm and idling. Throughout the life of the scooter and carburetor, you may need to adjust the air/fuel screw from time to time as the engine and carburetor wear, or if you change the altitude where you live by moving, or seasonally if they reformulate the gas at different times of year.
If you are under the impression that adjusting the screw changes how your scooter performs at speed, you will likely feel a performance change by taping an amethyst crystal to the top of the carburetor. If the screw is not adjusted correctly, you will idle off the throttle valve, and that can affect starting, the transition from the slow jet to the main jet and whether or not the engine surges at idle.

Thanks

Ok I'm getting to the news..

I dialed my screw to 1 turn out and it pick up speed at a lower speed than if I put it at 2 turns. I'm pretty sure it's the fact that the pilot jet spray gas all over the range to WO.
I'm not hallucinating I feel the power lose when I set the screw counterclockwise. What could that be.