Small frame Vespa scooters have only two jets: a main jet that the needle passes through, and an idle jet. Main jets come in various sizes, ranging from 37-88. This is the main jet for Vespa small frame scooters with 16mm and 19mm SH carbs. Also fits PHBG carbs.
Jetting is something that takes trial and error. See our blog page of for more info.
