Wards Riverside Wiring: Mongomery Wards in the late 1960’s sold a full line of motorcycles and mopeds made in Italy by Benelli (and also early 1960’s mopeds made in France by Motobecane). This is the 50cc sport bike model FFA-14003, a 4-speed foot shift manual clutch motorcycle.
Even back then, they used the ignition source coil ground to operate the brake light. Ground the green wire first to get spark.
Wards Riverside Wiring, Dansi 3-wire magneto, external ignition ground