My bike is a 1971 R75/5 with about 210,000 miles. I am looking to return the bike to somewhat "stockish" condition after running with an Avon Police fairing and Dnepr sidecar. The reason, it will be gifted to our son soon to pass along the enjoyment. My problem, among many according to my wife, is that I am completely stupid when it comes to electrical. It might as well be a different language. I can follow along the schematics for the bike, my problem is removing the added wiring when the fairing and sidecar where added on. OK until now. I am looking at the turn signals and will be re-installing the stocks and correct lights. I see the rear, which are set up correctly and working have a ground wire running to and through them. The front turn signals appear only to be grounded to the case. Wanted to ensure I am reading this correctly. I will then have to decipher the mess of wires leading to the headlight bulb holder as there needed to be extensions added as the headlight was mounted in the fairing. As sad as it is, I have owned the bike since 1974 and still can't get my head around wiring; even with the great articles from those who are kind enough to try to pass along some wisdom to the rest of us. I have attached a couple of pics to help. Probably simple as heck for some, not for me....
It's really very simple. The electricity always makes a circular "round trip". It starts at the battery. The battery feeds the light switch (headlamp or turn flasher). The switch sends power to the bulb. And then from the bulb it returns to the battery, either by attaching the second terminal of the bulb to metal portions of the bike OR by supplying a Brown wire to return it through the harness "Return" wiring. If you can handle driving to work in the morning, then returning home again in the evening, then you can handle electricity. The only difference is that electricity drives on "wires", while you drive on "roads". Other than that, it's exactly the same concept.
A typical circuit. Please ignore the ammeter.
• The stock headlamp is going to be a 3-wire affair. One White wire for Hi-beam, one Yellow for Lo-beam, and one Brown wire for return. All 3 wires connect up to same color wires inside the headlamp shell.
• Power from the turn signal switch comes into the headlamp shell on 2 wires. One wire is for Left turn, the other wire is for Right turn. Each of those wires is connected to 2 bulbs, 1 front and 1 rear. Typically, turn signals are not as important as headlamps, so their power may return through the metal shell of the /5 blinker pods. So there is no Return wire to see, but the function is still there.
Your schematic will tell you what color to look for inside the headlamp shell for left and right turn signals. It will be something like what's below....
Hope this helps.
Owning an old Airhead is easy.
Keeping an old Airhead running great is the true test.
This does help and I appreciate you making it less complex for my mind as well as the drawings to assist. I am using this down time in the world to try to increase my awareness and likely less nervous approach to dealing with the "dreaded" electrics. 🙂
• The main thing is NOT to let the quantity of wires inside the headlamp shell boggle your mind. There are at lease 3 main electrical systems on a motorcycle: ignition, charging, and lighting. They are absolutely and totally independent. But, all their wires happen to be wrapped into a single "harness". When you set out to bake a cake, you don't care that you find a steak and lettuce in your frig !! You're only after the milk and butter. In the same way, when you open the head lamp to work on turn signals, all you're interested in is the flasher unit and the wiring for the front and rear turn signals. Any components or wiring having to do with ignition or charging or brake lamps is totally superfluous.
• Any specific questions feel free to ask.
Owning an old Airhead is easy.
Keeping an old Airhead running great is the true test.
I like the analogy and certainly it makes sense. The reference to Etch A Sketch did have me laughing as well, certain reminder of younger times. With the added time on my hands, I have taken a big breath and will follow the concept of simple is the best way. Typical airhead thinking. Armed with your diagram and the schematics, and realizing that much of the added wiring is mostly extending the harness to reach the headlight in the fairing, I will be spending some time in my garage and SLOWLY working through this. I am confident these efforts will end successfully. Thanks for the info and your positive vibes. Soon I will report back that the headlight is back in, working, and the front turn signals are happy Only thing holding me back. I may not wish to gift this to my son at the end. 🙂 After 46 years of enjoying this bike (and having others in the garage) I guess I really will spread the enjoyment, so much easier knowing it will be within the family. Another Airhead, what a positive thought. He may get the bike, but I will retain visitation rights!
• As far as the headlamp is concerned, it looks like the easiest thing to do is simply shorten the head lamp wires to about 10 inches and re-connect them at the proper terminal. This is best done one wire at a time so that you don't confuse the terminals.
• If I was working on your turn signals, then I would take the time to run a new 20ga return ("ground") wire out to each front blinker pod. This would update the front turn signals and make them ever so much more reliable (and possibly brighter). Inside the headlamp shell those 2 wires would connect to any Brown wire or terminal with Brown wiring.
• In your photo I see the cylindrical can which is your flasher unit. Then down at the bottom is a black plastic terminal block with the Blu/Red and Blu/Blk turn signal wires. That's quite possibly where your stock turn signal pods re-connect.
All the best.
Owning an old Airhead is easy.
Keeping an old Airhead running great is the true test.
Well, the fun has ended for me. When I shortened the wires as suggested, which makes lots of sense, I ran into a problem. The turn signals were not connected but I wanted to check the headlight assembly to ensure it works. Some of the wires started to overheat and begin to melt. Pulled the key, stopped the melting but that is it for me. I know when my efforts are finished. I do thank you for your assistance but for some reason, I have screwed up and don't plan on touching it again. I will leave it for someone who has more knowledge and ability that I do. Obviously I did something wrong, possible missing a ground wire but that is it. Thanks again.
Would really like to know the end of this story !
Owning an old Airhead is easy.
Keeping an old Airhead running great is the true test.
As you can tell by the frustration in my story, I have sent it off to the dealership in Toronto for them to take care of it. I know not an "Airhead" way, but tired of the problem and can find no one who is dealing with the old bikes. All the local gurus appear to have retired so no other choice. We were to have an Airhead tech session in the Ottawa area but naturally was called of due to COVID-19.
Sorry to hear that.
My shop is always open. Ride 1500 miles due South, and take a Left when you get to Atlanta ! 😛
Owning an old Airhead is easy.
Keeping an old Airhead running great is the true test.
It sounds like a nice ride for me. Who knows what will happen next year. Always (not really) look for an opportunity to ride and meet new friends. Be safe.
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