Float needle for the Si carburetor. If the carburetor overflows, it often has to do with a faulty float needle.
The float needle is a wear part and should be replaced with every carburetor cleaning.
The component is so delicately crafted that defects in old and no longer properly sealing float needles may sometimes not be visually detectable.
This is an original Dellorto component in sprung-loaded design suitable for all Vespa Cosa 125/200 scooters.