A20 Petcock

A20. 12x1 female spigot left medium shaft

A20 12×1 spigot left
medium shaft
229169  $22
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Taiwan-made by FS

Links to photos of examples:

1978 Moto Guzzi Robin original
1979 Benelli G2 original
1995 Tomos Targa original
1998 Tomos Targa original
2005 Tomos ST original

Benelli G2 The valve shaft sticks out of a small hole in the plastic side cover. The black handle knob must be pried off (with two screwdrivers on opposite sides), to get the shaft through the hole in the plastic side cover. The valve must be aimed just right. It might take 2 or 3 guesses to get the shaft aimed at the hole. Then the plastic cover is replaced, and then the handle knob is pressed back onto the shaft.