Welcome to the Airheads forum, Rudy.  Is it possible that the kill switch was thrown?  This would show as a complete loss of power. No instrument lights and no electric start.

Did you try to jump start the bike?

 The first step in electrical trouble shooting is to start with a known, good battery that is fully charged. I like numbers when thinking of airhead electrics. Do you have a volt/ohm/amp meter (VOA)? What is the resting voltage of your battery at the terminals?, and what brand of battery are we considering here? Next would be a load test on the battery. When a load is applied to the battery, the surface voltage will drop. This is due to the battery issuing current (amperes) to a device, like a starter motor. You can take the battery to any auto parts store like "Auto Zone, etc." for a load test, or you can purchase a hand held load tester at automotive stores like "Harbor Freight".

 "turned the bike off to cool down and noticed my bike was whistling (low pitch sound) from the central area around the battery".   Was this sound coming directly from the battery? If so, one would suspect that the battery was being cooked by a voltage regulator that is not regulating. When a voltage regulator fails to regulate, the alternator output increases with engine RPM beyond a desirable voltage somewhere around 13.5v, and increases to 16v or higher. When this happened to my bike, with a wet cell battery, it would evaporate the acid in the cell closest to the positive terminal, and pop the headlight elements.

"no luck the bike will not start- no power."                                                                                                                                      If/when you have a known good and fully charged battery, the next link in the chain is the starter relay.  When we get to this point, there are a great many possibilities. The starter relay is like an electrical gate keeper. All the battery potential for the control system devices ( main key, starter button, turn signals, etc.) are routed through a parallel jumper connection inside the relay. The only device not associated with the relay is the big wire that delivers current to the starter motor.   

As you can imagine, electrical diagnosis over the internet is challenging at best. Start with your battery and then report back. 

Best of luck,

James A...                                                                                                                              

Hello James, 

Thank you for the possible prognosis. I think it could be the regulator as mentioned. Forgot to mention, at the time of this occurrence and apart from the whistling sound, there was an unknown & strange smell emitting from the battery area. 

Secondly about a month ago, I did have a volt meter operating on my well keep R100 and it shorted-out unexpectedly, this event drained my old battery. At the time, I had the bike checked out by my trustworthy local BMW mechanic and purchased a new Yuasa battery- everything was operating well until last weekends ride.

I'll continue my exploration on this matter and we'll keep you posted, much appreciated. 

Regards, 

Rudy H.

When a battery is being overcharged, the sulfuric acid electrolyte inside boils and emits sulfur dioxide. This might be described as a "rotten egg" aroma.

Rudy -

Welcome Aboard !

The advice James gave you was spot on. I can only add some "icing on the cake"....

• Battery condition changes in ways that don't make sense (unless you study batteries), which is why you need a "battery load tester". Any store that sells batteries can run the test for you, usually for free. 

• With a VOM across the 2 battery terminals....
Engine not running, your new battery should read around ~12.6 VDC.
Engine running at 3000 RPM, battery voltage should read ~14.2 VDC.

• I highly advise ditching the OEM mechanical regulator (regardless of what you find) and replacing it with a modern solid-state version. These have been on the market for 20+ years, so they are easy to find for roughly $20. There is the standard one for traditional liquid-filled batteries, and Mottorad Elecktrik sells a special one for sealed AGM batteries.  http://motoelekt.com/charging.htm

Hope this helps

Hello James & Richard, 

Thank you for sharing your insight, I'll be proceeding as indicated, please stay tune for results.

It's so helpful having you Gents around for the knowledge needed to keep these wonderful bikes rolling!

Best Regards, 

Rudy

Posted by: @wobbly

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• I highly advise ditching the OEM mechanical regulator (regardless of what you find) and replacing it with a modern solid-state version. There is the standard one for traditional liquid-filled batteries.... These have been on the market for 20+ years, so they are easy to find for roughly $20. 

Here's a modern solid-state one for a standard battery on Ebay for $17...  HERE.