1973 AT3 Electrical Question

[KJDonovan]

Greetings all,

I’m new to this group so I should probably start by introducing myself, my name is Kevin Donovan, and I live in Foster RI. I am mainly a Penton guy, but just picked up a 1973 AT3 125 and needless to say, I have lots of questions.

Anyway, last week I picked up a 73 AT3 125 for my wife. The bike is not running but it has lots of potential, good compression, 95% complete and 720 original miles on the clock. The bad side of this machine is someone monkeyed with the electrical.

I guess my first question is with the electric start. Based on the wiring diagram I have started filling in the blanks so to speak on the harness (it looks like the previous owner got a little happy with the wire cutters). Now I am at the point where I can turn on the key, the neutral indicator light works, the tail light and brake light works, horn works and the headlamp will work as soon as the new switch comes in (tested it with a jumper).

As for the electric start my question is with what looks like a starter solenoid, its mounted to the frame under the tank, aft of the coil. When looking at the connectors on the solenoid (facing forward) on the right side there is a large connector with a heavy green wire that goes to the generator / stator, also on the right side brown wire and a blue with a white trace that goes to the starter button. On the left side there is a dual black wire that connects to the side (looks like a ground). The piece of the puzzle I am missing is the second large (6MM) lug on the back left side of the solenoid, has nothing connected to it. My guess is that something needs to be connected to this but I’m not sure what? I know if this was a 64 Ford, it would have a hot lead from battery connected, but I don’t want to just try that without knowing.

Any ideas anyone has would be appreciated.

Thanks in advance,

Kevin Donovan