1978 R100/7 : all components within the charging system are new and functioning correctly, strong battery, brushes/springs in good order, clean rotor surfaces, no loose wires up in the Speedo/tach housing, etc. etc.
The problem: the red charging light will go on, albeit a slight flicker on again/off again with the bike running at 3000 plus RPM. Not at lower RPM, just the mid-upper end of the tachometer range.
The light goes on when the key is turned on, goes out once the bike is started, as it should.
Problem existed before and after installing a Katdash for the bike.
Any thoughts?
I’ve never really understood how that light works, so I really can’t help - but, the light should be on at idle speed, then gradually go out as rpm’s rise. I think it should be off by 14-1500rpm or so. I’ve seen mine glow dimly at higher rpm’s when riding in the dark. Rick Jones once told me that is not too unusual for an airhead. it’s a strange circuit with that bulb, kinda like it is “hanging in the balance” in some kind of series circuit.
I had a similar issue on my 75 R 90. I tried everything with no joy. One day I unplugged the signal flasher unit. Problem resolved. If I put the flasher back in the problem returned. Replaced the flaher unit with an automotive 3 prong one and all is well with the generator light.
Cheers!
John
The Alternator output warning lamp is 100% controlled by the Voltage Regulator. The OEM voltage regulator is an analog device composed of relays and contacts (like "ignition points") which open and close. No owner would expect a set of ignition "points" to be good after 50 years, but here we have the same setup inside the 50 year old VR. What could possibly go wrong?
Bosch themselves stopped make analog VRs about 1990, when they converted over to a solid-state VR that operates much better, and works by controlling things using transistorized circuits which have no moving parts. The Bosch design originally used on Airheads was also in common use on a lot of period automobiles (Saab, Volvo, Mercedes...), meaning you can still buy plug-compatible solid-state VRs very cheaply. And this is where I suggest you start.
Or, you can buy the equivalent device from Motorrad Elektrik for $39 from the bottom of...
Owning an old Airhead is easy.
Keeping an old Airhead running great is the true test.
1978 R100/7 : all components within the charging system are new and functioning correctly, strong battery, brushes/springs in good order, clean rotor surfaces, no loose wires up in the Speedo/tach housing, etc. etc.
The problem: the red charging light will go on, albeit a slight flicker on again/off again with the bike running at 3000 plus RPM. Not at lower RPM, just the mid-upper end of the tachometer range.
The light goes on when the key is turned on, goes out once the bike is started, as it should.
Problem existed before and after installing a Katdash for the bike.
Any thoughts?
- I should close the loop on this, but the problem was resolved as of yesterday. Not sure which blue wire from the diode board it was (either the one going to the white plastic connector next to the x2 relays or the one going to the plug for the voltage regulator), as they were cleaned at the same time, but red light no longer flickers at high speed.
I should close the loop on this, but the problem was resolved as of yesterday. Not sure which blue wire from the diode board it was (either the one going to the white plastic connector next to the x2 relays or the one going to the plug for the voltage regulator), as they were cleaned at the same time, but red light no longer flickers at high speed.
As I have written here at least 100 times... Back when these bikes were new they were ridden cross country in all sorts of weather... and then washed. Water enters the connectors (either by wind pressure or power wash) and then proceeds to corrode the connector. Your bike is now 50 years old ! That's a LOT of water given the opportunity to create a LOT of corrosion !
My point is this... it is HIGHLY unlikely that all that water picked out 1 single connector. Common sense dictates that all your connectors received the same water treatment sometime within the last half-century, and therefore you will have (most likely are already having) the same issue with other connectors, most of which will NOT be as evident as a blinking indicator lamp. I talking about low charge rates, dim lamps, not-so-loud horns, slow blink rates on turn signals, etc, etc.
To further complicate things, you may have polished the male connector during your cleaning/repair. Polishing the male connector would simply strip off the protective over-coating on the brass contact. The zinc, tin, or lead over coating is placed on the brass connector precisely to prevent said contact corrosion. So now the "contact cleaning" may help the corrosion return even faster.
When I worked as an engineer in a telecommunications research lab we used No-Ox-Id (made by Sanchem), a compound that protects connectors from water and promotes electrical connection. (This was back in the pre-cellphone days when ALL phone service was by copper wires.) I immediately turned around and started using that compound in my professional vintage motorcycle work, because it was evident to me that both systems suffered from the exact same issue: water intrusion. When I switched from classic English motorcycles to vintage Airheads I discovered the exact same electrical issues.
I say all that to suggest that if you want to eliminate this issue over your entire motorcycle, then you should buy the smallest container of this anti-oxidation compound and simply start applying it to every connector as you do your regular service and repair work.
Suggested reading: https://www.airheads.org/community/wrenching/home-mechanic-electrical-corrosion-on-connectors/#post-15709
Owning an old Airhead is easy.
Keeping an old Airhead running great is the true test.
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