A19 Petcock

A19. 12x1 female spigot back short extended knob

A19 12×1 spigot back with short shaft
Left is original, right is replacement
It is a A15 with a longer handle shaft   $27
←reserve  on↓ off→   OMG made in Italy

Links to photos of examples:

1985 Garelli Rally SL original
1985 Garelli Rally SL original

Garelli 1980-86: This valve is made for the 1980-86 Garelli Sport, Rally Sport, Rally SL step-thru models with side panels that cover everything up to the bottom of the gas tank. The valve handle shaft passes through a hole in the panel.

The replacement sticks out a few mm farther than the original. Not bad.