Oops looks like my video won’t upload. I’ll have to figure something else out. 

It might be nice if we knew the year and model of the vehicle in question.

Good point Richard. This is a 1980 R100RS. Has the dual spark option. Thanks

Link to videos below. The sound and flickering instruments originally only happened once I turned the ignition switch. It flickers and makes the sound when just turning the key. The starter button does nothing. 

https://youtube.com/shorts/Wc8YDmnUdS4?si=con7FmHc4vL0nAG-

https://youtube.com/shorts/no2IjPR84ew?si=t0XcdiJlzoU6Mixg

I could write a short story about an episode I had with my ‘78 R100 while in Baton Rouge, LA. The electrical symptoms were all over the place. I, too, had strange noises and flickering lights … though the bike might start … then it would quit, dead, etc.  It all turned out to be a failed 13 month old WestCo sealed battery. Some internal fault in the battery … it was truly crazy. New battery and I was good as gold.

PS:  My riding buddy and I thought it was the ignition key switch, cuz of the way it behaved. 

Interesting. Thanks David. I wonder if there is a way I could test for that. My current battery isn’t all that old but it may have seen some wear and tear. The previous starter/stator pair was draining and barely maintaining it. After I replaced everything I had a faulty regulator that was sending too much charge to the battery. I only allowed it to run this way no more than a couple minutes though. I’ve load tested the battery several times and it has always checked out. 

Bummer. Tried a new battery and got the same flickering and sounds. Nothing from the starter button.

Some thoughts.....

• If you suspect the ignition switch, then completely unplug it and directly jumper Red (Batt) to Green (Ignition). Ignition switches do fail. BMW no longer offers a replacement. You'll need to call Motorrad Elektrik for a pattern replacement.

• Why is your Voltmeter pegged out at 15V ??

• Why are you "pairing" the starter motor and the alternator ? They are 2 completely separate units from 2 completely separate parts of the electrical system.

• Does your bike have the under tank front brake master cylinder ? If so, then replace the old Starter Relay with one of THESE after coating the male contact terminals with THIS STUFF.

@eric-druse bummer, your symptoms seemed similar.  We had actually gone so far as to replace the ignition switch with a toggle switch … and the bike started and ran. Then, in a few miles it quit again. That was the only time I ever had to have the bike picked up on a tow truck. Took it to Herbert BMW in Baton Rouge. Much time and expense later, was found to be the stupid battery. One month out of warranty, and WestCo was no help at all.  Never bought one of their batteries again.

I had a similar thing happen.  You say you did electrical upgrades, recheck your work.  Not only the positive connections but ground connections as well.   I am sorry I can't tell you which connection solved my problem because I spend a year chasing the problem and after pulling and cleaning ALL terminal blocks, and connections I fixed the problem.  The reason it took a year was because I just didn't sit down and do the job in one day, actual time to do the job would have been to put music on in the shop and just start checking, rather than check one spot then ride fail and then a few days later check another, if you get my drift?

Switches do fail, I like Richard's/David's idea of bypassing the ignition switch.  Also as he says, the starter relay could be an issue.

Frankly, starter relays fail a lot more than do the ignition switches.  

As for the Voltage meter at 15 volts, I would say it depends on what voltage meter you are talking about?  The in dash meter is not a precision unit, it is pretty good but in my experience with three bikes, I have seen a plus or minus one volt difference between what the in dash unit showed versus what a true voltage meter test unit showed.   LOL, the in dash meter in my eye is just a good indication of charge health, not a true troubleshooting device.   Check your voltage at the battery terminals with a good meter to see what the true reading is.

Good luck and good hunting,  St.

I put the cart before the horse, I wrote my reply before listening to the videos.  I would guess, the starter relay is bad just from listening.   Still I would recheck any work.   St.

Thanks all for the feedback.

There has definitely been a leak or two from the brake master cylinder which is under the tank and just above the starter relay as you describe. That sounds like a good lead to troubleshoot.

I am going to try the ignition switch bypass as well.

The voltage meter is dead and has been stuck like that. I wouldn't think that would create an issue now as the bike has run fine for some time outside of current issues.

I definitely understand the separation of the starting and charging systems now that I have worked through and replaced multiple components. When I described the starter/stator being an issue I meant my starter was a weak original bosch on its last leg and the stator was also failing. The bike was incredibly difficult to start and the gen light was almost always on unless I was well in the RPMS. Now the bike fires right up and I have a consistent max voltage at 3000rpm around 14v. During this process of working on the charging system the first voltage regulator I received was bad at I had 16v at the battery at idle. This is an aftermarket charging system from EME.

Will report back. thank you

Posted by: @eric-druse

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There has definitely been a leak or two from the brake master cylinder which is under the tank and just above the starter relay as you describe. That sounds like a good lead to troubleshoot.

I am going to try the ignition switch bypass as well.

What you don't understand is that 100% of the system electrical power goes through the 2 contacts on the Starter Relay. Thus, 1 component gives you 2 chances for horrible electrical connection that affects every single electrical system and component on the bike !!

I wouldn't be surprised to find out that this was your primary issue all along. You'll want to wash the entire area with HOT soapy water to get rid of the caustic brake fluid and any residual. Then, rebuild your leaking master cylinder. Then, apply a corrosion and oxidation compound to EVERY single electrical connection in the area. This has been covered on this forum many times since 2016. Read THIS.

Posted by: @eric-druse

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The voltage meter is dead and has been stuck like that. I wouldn't think that would create an issue now as the bike has run fine for some time outside of current issues.

The voltmeter is your best on-board diagnostic tool. Why in Heaven's name are you riding around with a broken voltmeter? 

Hope this helps.