tail light hook up

I'm looking to side mount a 32 or 33 ford brake light on my 1974 850 commando. It only has two wires not three like the lucas light. I know the bike is a positive ground system but im wondering if the 2 wire light will work fine. Also would a LED light work? I donn't know much about electrical. the light has a wire for the running light and stop light and says it is ground interally. Any input would help so I don't waste my money on something that will not work. Thanks.

Sounds like you need to ground the metal case on the Ford light housing. Attach a ground wire to one of the mounting bolts. You could try it with some jumper wires off a battery before installing it.

It should work. It essentially has 3 "wires". Two for the lamps, and the metal enclosure acts as the 3rd "wire" by bonding the positive side of the light to the grounded frame. Should be able to run the positive wire from the bike to any metal componant of the light fixture.