Charging system?

[uncle mark]

Hello All
I am trying to help a friend with a charging problem on his 78 R80/6. The charge light stays on and Duane told me to try a rotor of known good quality. I was hoping to find a good explanation of the charging system, I tried reading snowbum's site but I fell asleep. Is there a good overview that an old guy could understand.
Thanks for any and all sources.

Uncle Mark

[Deleted User 62]

I found these pages to be very helpful (click on the pics): NOTE: make sure it is the generator (red) light that is on...

[Kurt in S.A.]

Call Rick Jones at Motorrad Elektrik. His booklet on boxer charging is just about required when owning an Airhead. He might be out of the booklet itself, but sells a DVD as well.

Kurt in S.A.

[Jean]

You need some caffein.
Both when reading the book and when doing the tests.

For a quicky, use your bench voltmeter to check the voltage at the battery when the engine is running about 3000 rpm. If it is not over 13 volts...you have a charging system problem...It could be the voltage regulator tho.
Rick's book says if the light stays on, the voltage regulator is suspect. The voltage reg. is under the gas tank. You might be able to unplug the wires if you can find it and reach the plug. Short the blue and black wires with a little jumper, in the plug, and run the engine over around 2000 rpm. If the light goes out, the voltage reg is bad.
IF that doesn't change the light, THEN you've got alternator or diode board problems.
The charging light is in the power supply to the rotor, so if it is ON, it suggests the rotor is OK. If it does not come on when you turn the switch ON and before the engine is running, it says the rotor is bad or you have a wiring problem.
GET back on Snowbum's site and read again...

[uncle mark]

Thank you all for the help and I am going to reread snowbums site as many times as it takes till I have the zen moment of understanding.
Thanks again
Uncle Mark

[Kurt in S.A.]

After that, read some more:

http://www.buchanan1.net/charge.shtml
http://www.largiader.com/articles/charging/
http://jhau.maliwi.de/mot/r-elec.html

Kurt in S.A.

[Jean]

Buchanan's diagram and text is rather easy to read. His diagram shows plainly what you are doing when you put the jumper across the blue wire and the black wire as described in the "voltage regulator test".
It also helps you to understand what is really on the diode board.
Print it and start your own electrical troubleshooting manual.

[uncle mark]

Those links were exactly what I needed. Thank you all for your help.
Uncle Mark

[Jean]

Be sure to follow up with what you find and fix so someone else can benefit from your experience.

[jjwithers]

Tim, can you please post the page that got cut off regarding testing the alternator?

I am unaware of how you can bench test them and I have a few lying around.

Thanks!