I salute your efforts to return the bike to stock condition, and admire your energy and resources to replace those 2 flasher pod mounts. That's a lot of work for what appears to be a small return.

To Your Issue
In cases such as these, most of the time you don't need to look any further than the DC Return path (what most people would call "ground"). In order for any electrical device to work, it's obvious that electrical power to reach the item, but just as importantly, that same power must Return. This is why it's called a "circuit"... which comes from the Latin for "circle". So when electrical trouble strikes, people look at the obvious supply wiring, but may never investigate the equally important Return path. On older vehicles, such as Airheads, the Return may not incorporate electrical wiring at all, but instead rely upon a chancy design called "grounding through the frame". This missing wiring is in fact the very reason for the problem. Later models (after ~1980) did incorporate Return wiring, which is why similar issues on newer vehicles have disappeared.

Suggestions
• If you'll remove your head lamp and one of the flasher pod lens, you can probably connect a test lead from the Brown (system Return) portion of the multi-color circuit board to the interior of the signal pod. If this corrects the problem, then run a 20ga wire from the pod, through the stem, and to one of the spare Brown positions on the circuit board.

#31 are the Return terminals in the lower RH corner

• Also, it's important to understand how these systems work. Original equipment incorporated a bi-metal flasher unit. This unit works on having a VERY strict resistance applied. If the flasher pod bulbs are ever replaced with "Heavy Duty" bulbs of a higher resistance, then the system slowed and wouldn't perform properly. Conversely, if the flasher pod bulbs are ever replaced with low resistance "LED" bulbs, then the system sped up and wouldn't perform properly. So the OEM flasher unit MUST have the correct wattage bulbs in place to function correctly. This is why modern systems use a much more expensive relay to control the flasher function.

99% of all turn signal flasher issues lie in one of those 2 areas.

Hope this helps.

Thanks so much, Wobbly for your explanation and suggestions I will give them a try and get back to you with results.
I have owned several BMWs for daily riding and touring over the years but always wanted an older airhead and finally picked up my R90 a few years ago and have been replacing and repairing things along the way. I just love riding this thing and joined the airhead owners club when I bought it. Being retired gives me the time to do my own maintenance and repairs and I really enjoy the process. The airhead group is awesome.

Being retired gives me the time to do my own maintenance and repairs and I really enjoy the process. The airhead group is awesome.

And you're going about it the right way too. YOU have to become the ultimate authority on YOUR bike. And you become your own expert by working on every part of the bike when every issue arises.

You simply must if you want to continue riding the bike because all the professional experts are dead and gone. At the end of your life you'll end up with a brain the size of the Encyclopedia Britannica, chock full of knowledge.... that's absolutely worthless to anyone else !! 😆

All the best.

Checked everything yesterday and tried running grounds to the signal pods. Still no joy.
I continue to have the dimly lite dash light for the signal indicators. This winter I rebuilt the forks, cleaned and lubed the steering head bearings and installed new shocks. So had the whole front end apart to do this work. Could I have disturbed something along the way? I have looked at everything I removed and reinstalled and everything looks good. Today I will remove all the signal bulbs and see if anything changes.

• Did you check the signal bulbs to be the correct Wattage ? As was stated previously, that's mandatory.

• This is also they type issues you get when there is corrosion on the electrical connectors. The corrosion adds resistance to the circuit, which throws off the delicate balance of the flasher system. This could be corrosion on the base of the bulb, or corrosion at a wire connection, or BOTH ! Over the last 3 years I've managed to treat every single connector with a compound name No-Ox-Id which you can get off Amazon. It's a compound that cuts through corrosion to make a better connection, and it protects the connection from further contamination. The smallest tube they carry is enough to treat 5-10 motorcycles.

I pulled the bulb and the dash light still remains on and I believe the bulbs are 21 watts. I have looked at all the connections and think I did a pretty good job of cleaning them. I hate to send it in to a shop to have someone else try to figure this out but it may come to that as my diagnostic skills are obviously pretty limited.

It is usually the last thing that you did before the problem occurred. Have you checked the throttle area wiring for shorts and bad connections.

Are the 4 way flashers stock? My wiring diagram for a 76 R90 does not include a 4 way flasher circuit.

As a troubleshooting step, you might try deenergizing the 4 way circuit. I would imagine it does not require the key to be in the on position for it to operate.

The power for the flashers, brake lights and horn is supplied via the top fuse. The green wires connect here. They should only have power if the Ignition is fully on. Thus, If you put a volt meter or test lamp on the fuse connection with the Ignition switch on you should get battery voltage (+/- 13 volts or a bright light). With the Ignition switch off you should see zero volts or no light. Anything less than battery voltage or a bright light with Ignition off would lead me to believe that Ignition switch is faulty.

SF

This makes sense. I checked the connections at the handlebar switch and they look good. The four-way flasher switch has a light that always was dimly lite since I have owned the bike so I always had it pulled up enough to disengage the switch. the dash light remaining on is a new development.
The four-way relay is under the tank and is original and looks old and pretty crusty looking I did clean all the terminals attached to it with no improvement so this has me thinking maybe a faulty relay for the four-way system also the blinkers have always worked with the ignition off so maybe a new relay for the four-way might be the answer I will run your recommended test later today.

It is great to watch two dedicated Airheads working together on a problem! I look forward to reading the solution. I must admit, when faced with a similar situation on my barn-find (after removing a fairing/wiring as well), I gave up and replaced the wiring harness. I must admit, it is good to stop worrying what will happen next, but I miss the exhilaration of the hunt! Best of luck, I'll be rooting for you guys!

... the problem is even with the ignition off, the blinkers work and the blinker dash light faintly glows. I should add that the bike has a four-way emergency flasher that also glows faintly with the ignition off.

As a troubleshooting step, you might try de-energizing the 4 way circuit. I would imagine it does not require the key to be in the on position for it to operate.

My bad. I misread the issue as a failure to properly flash at the correct rate, not a "will not stop working".

SF is correct. Your entire turn signal system is powered by the Grn/Blk wire which comes through the headlamp fuse and starts out as Green from the ignition switch. As such, none of this should have 12V applied with the ignition switch OFF. By clipping your test lamp to the Brown section of the headlamp circuit board and then probing around, you should see ZERO power present at either fuse with the switch in the OFF position. Conversely, you should ONLY see the presence of 12V when the switch is turned to the ignition ON position. A simple enough test.

I would assume that a 4-way flasher is supposed to work with the ignition switch OFF. This brings up several areas of investigation...
• If there is no power at either fuse with the ignition switch OFF, I would assume 12V power has to arriving from the 4-way flasher system (since that's the only electrical item with any power in the ignition switch OFF position).

• Since no 4-way was offered in 1976, I'd want to be investigating exactly how this system is powered. 1) Because it's most probably powdered from the system Red wire which has NO fuse protection. Are you really willing to smoke a $300 main harness in order to have a 4-way flasher that you use (what ?) maybe 1 time a year ? 2) Unless your ignition switch has failed and is allowing power to components with the key in the OFF position, then the mysterious power source must be power bleeding through from the 4-way system. You can easily prove that to yourself by finding the 4-way power connection point and disconnecting it.

• Since no 4-way was offered in 1976, I'd want to be investigating the general workmanship. When I first got my RT there were many mods made to the harness including remote fuses, extra running lights, a CB-radio-intercom communication system, and other electrical "enhancements". Back in 1979 'remoting' the RT fuses was seen as the thing to do, but unfortunately this installation was done with common household lamp cord. This type wire is not soap, gasoline, oil or UV resistant, and the insulation was starting to crack and come apart. Some of the communications wiring was done with solid core home telephone wire !! In all, I pulled a pile of wiring off the bike that was 3 ft in diameter and 1 foot high. I wish I had a photo !

My point is this, if you're not seeing the 4-way unit wired with automotive type, multi-strand wire... using soldered connections and heat shrink.... wiring that is basically up to or above the standard of the stock BMW harness, then you are better off to remove it now. Motorcycles are the toughest electrical environment on the face of the Earth, and unless all of your wiring meets the high OEM standards, it is simply destined to give you trouble.

If getting the fairing back to OEM was a good thing, then getting the electrical system back to the same place can't be far behind.

Hope these thought help.

I didn't have much time today to spend on the bike but on further examination of the relay for the four-way under the tank, I found two of the four spade connectors on the relay to be pretty loose and as I said before the relay looks all 44 years old that it is.
I did pull the red power lead from the relay and that shut down the whole signal system. could a faulty relay be my problem? It's a 15AMP relay and BOBS has them for about $55.00 That's hard to swallow so kinda looking for a substitute if possible the part # 61321358198 I think its a bosch.
BMW offered the four-way flasher system as an option in 1976 and I can live without it no problem but if its just replace the relay thats a pretty easy fix. I will do some of the other testing suggested in the next day or two.

• If you intend to keep the 4-way, then you REALLY ought to place a 5A fuse in the wire coming from RED into the 4-way relay !!

• If your relay has a schematic on the side, often times you can buy the same relay from Amazon for ~$6. Simply compare the schematics.

Thanks again Wobbly, I bit the bullet and ordered the new relay from Bobs last night figuring I might as well have the correct one and I will take your advice and install a fuse on the red power wire to the relay.
Hopefully, this will resolve the problem. I do have Snowbums schematic for the four-way flasher system and will run through that also.
I will report back when the new relay arrives.

To my American way of thinking, the OEM wiring leaves somethings to be desired. ANYTHING connected to the Red wire has no fuse protection at all. That means at the first sign of trouble the entire harness goes up in smoke. Now granted, not much is connected directly to Red, but it's a favorite place to mistakenly connect aftermarket accessories.

One stock item that is connected to Red is the clock. And I had a clock short out internally, which smoked the fairing harness and the main harness. From then on, I placed my own 1A fuse between the clock and the harness. It's an easy thing to do with a weather-proof flat pack fuse holder and some crimp ends. Such as below....