Modern Vespa

1979 p125 x runs great but a flat spot just above idle(1/8) throttle. i rebuilt carb same thing. new points ,conden, coil wire, plug Stock jetting,only 600 miles since new

Certain all the passages in your jets are clear? Absolutely positively clear?

Another thing is carbs have little tunnels and passages in them that can be blocked by the tiniest piece of grit or varnish, or gunk. Sometimes blowinig them out isn't enough, you need to soak the whole darned thing in a gallon bucket of Gunk Carb cleaner.

Emoticon translation-

(1/8) throttle = 1/8 throttle

8 + ) = 8)