A24. 12x1 female side mount Maxi
Links to photos of examples:
Puch Maxi: The most popular 1970’s moped in the USA uses this valve. Puch Maxi and Maxi equivalents GN, Rigid, Sport, Sport MkII, Newport, Newport-L, Newport II and Maxi II all have the same sheet-metal gas tank built into the frame. The gas valve is on the right side mounted horizontally.