Alright, I made some progress. I should have mentioned in my original post that the engine runs well. No trouble there. I got a voltage regulator, installed it, and got the headlight to work. The high beam indicator light works too.

A couple things to sort out: Rear brake switch works, but the front doesn't. I traced the wires and think I have everything wired correctly, but I might not. I have a male green wire without a home at the moment, and that might be part of it. Horn isn't working, but I think that's because the horn is bad. The backlighting for the tach and speedo also doesn't work, which I thought was odd given that the high beam indicator light works.

Thank you both for your help, really glad to have the headlight working!

Halfway there then, excellent!

The front brake light should have lightish brown and green/yellow wires, just like the rear one in fact. Just make absolutely sure that the brown female multiple connector that the brown is plugged into is the positive feed and not the one for the indicator.

The only bright green male connector should plug into the top headlight terminal. The right hand side indicators use dark green wires, although these aren't as easily confused as the brown ones are. Again, just check that you have dark green going to dark green.

If the horn isn't working at the moment, then before you replace it (they are quite cheap), you could try the following:-

1) On one side of the horn should be a single screw/bolt, possibly with a small locking nut. Once this is free to move, try the horn as you screw it in for quite a few turns until you can go no further. If no good, try it whilst turning it out until it is loose or totally out. The horn works by way of a vibration caused by an electro magnet and a set of contact breaker points.

2) If (1) above doesn't work and the two halves of the horn are held together by screws or nuts (some are riveted together), then undo all the screws/bolts and prise the two halves of the horn apart. You might want to take photos of how things are assembled, just in case...........!

You should see the small set of points. Gently prise them apart and clean the two faces with emery cloth or something similar. Clean any other corroded surfaces and electrical contacts.

You can actually get the electro magnet to work whilst the horn is apart - I found that quite amusing, although it has to be said that I'm easily amused! Anyway, reassemble the two halves of the horn and go back to step (1) to try and get it to work.

If no good, replace.

You have checked that the back lighting bulbs all work ok?

Getting closer!

I now have everything working except the turn signals... which are in the mail. Not necessary to be street legal in the Nation's Capital, but I think it's better to have them just in case. Now on to a new question.

That's terrific news!

Don't forget to post how you fixed things - this might benefit other forum users in the future who have similar issues.

Is your flasher unit present (located under the fuel tank, just forward of the ignition coil)?

Well, the biggest problem for me ended up being that some wiring and connectors were missing. I think the previous owner disconnected everything, lost some bits while everything was disconnected, and put things back together as best as he remembered. What ended up being most helpful to me was to pretend I was wiring the bike from scratch, tracing every single wire and making sure its route made sense.

I replaced the horn. Would have liked to repair the one the bike came with (not sure if its original) but I couldn't get it apart without destroying it. Tried some contact cleaner in addition to what you suggested, but no dice.

Yes, the flasher relay is present. I haven't tested it yet though.

Thanks, and top job on getting it all working again .