charging problem

[mtpica]

I've got a charging problem with a 1982 R65 that I recently purchased and thought I'd seek some advice here before diving into troubleshooting and component swap with another R65.

The Gen light comes on when I turn the key to the first stop just as it should.  

When I start the bike, the Gen light goes out and stays out at idle.  

When I increase rpm, the Gen light flickers on and off dimly, sometimes stays on dimly, and sometimes flickers on to full intensity.  The Gen light usually goes off as the engine speed returns to idle.

Any thoughts on what I might be dealing with?

thanks!

Mark
1982 R65
1984 R65
1982 R100 RT

[nothing]

Worn alternator brushes.

[Paul]

I had this same problem.  It was an open on the rotor.  Once the rotor was off and in good light it was easy to spot the break in the wire.  Motorrad Elektrik (http://www.motoelekt.com/charging.htm) has rotors in the 90 to 100 dollar range.  The entire charging system could be replaced with a higher output system from Motorrad Elektrik ($575) or Euro Motoelectrics ($475) http://www.euromotoelectrics.com/enduralast.html

You could test the resistance of the rotor to make sure before spending a lot of cash.

Paul

[Justin B.]

Most likely a brush issue.  Both rotors I have had go bad opened and the GEN light was always off with this condition.  Could also be the brush springs not putting enough pressure on the brushes...

[Paul]

When my rotor went, the generator light would come on dimly at high rpm.  However, I hope it is the brushes.  It is a much cheaper fix.

Paul

[Justin B.]

In both cases where my rotor had "opened" the GEN light did not come on when I switched on the key, since he stated the light comes on with the key there's hope he just has a brush issue.  But, I have read accounts where the rotor windings will have an internittent internal failure so that it only shows up once the revs and cent. force increase.  I bought both of my new rotors from Rick (Motorrad Elektrik), aftermarket at something like $99.99/ea.  If I was going to put on an aftermarket alternator the one sold by Euro Motoelectrics looks very interesting...

[Paul]

When looking at the alternatives when my rotor went out, I do not remember seeing the system from Euro Motoelectrics.  At the time I went ahead and upgraded to the Omega Charging system form Motorrad Elektrik.  The fellow at Motorrad Elektrik has been really helpful and friendly the couple of times I have spoken with him.  The upgraded charging system has allowed me to commute battery charger free, even with a BMW gel battery.

Paul

[Bob_Roller]

A quick check that I did when I found my brushes had worn down, was to pull up the 'snail' spring that pushes on the brushes, and put a small piece of plastic on top of the brush, and then let the spring back down. It provided enough tension on the brush , until I could get replacements. If you have a repair shop locally that rebuilds starters, alternators, and generators, they most likely can supply you with the needed brushes.

[mtpica]

Update:  

I replaced my extremely worn alternator brushes, turned the key to the first stop, and the generator light came on just as it should.  I started the bike, reved it a bit, and....................    
 
........the Gen light still flickers on and off dimly, sometimes stays on dimly, and sometimes flickers on to full intensity.  The Gen light still goes off as the engine speed returns to idle.

I guess I'm looking at rotor replacement!  

Thanks for the advice; has anyone by got a good used, inexpensive rotor to spare?

mark
mfitzsim@aol.com
1982 R65
1984 R65
1982 R100RT

[MrRiden]

Have a VOM? Checked all other connections? Your probably correct in your diagnosis but... before pulling the trigger on the wallet why not make a few checks. You'll find some good guidelines at http://tinyurl.com/33dlvj
but if you already been there done that here's a link for parts. This guy does show up a rallys with his wares for sale and has a good reputation among the AirHeads.
http://www.motoelekt.com/charging.htm
rich

[msbuck]

OK, this is a completely different train of thought, but I thought I'd put in my  [smiley=2cents.gif].  Check all your contacts including your starter relay ( I THINK that's where my problem was years ago.)  I had the same thing happening.  I took it to my local airhead expert and he found alot of dirt, etc (like an animal's nest even) where it shouldn't be.  He cleaned the thing up and I've had no problems since... with that particular issue, I should say... :-/ )

[dewjantim]

The bad rotor on my R80 did the same thing. Replaced it with the same one taken off the bike (just because it had over 100,000 miles on it) and it has been OK ever since. Dew.

[Justin B.]

Mark, it still would be a good idea to at least "shim" youir brush springs as Bob suggested.  When the spring tension gets too low the brushes will not be held in proper contact with the slip rings when the revs are increased.  Not saying this is the fix but is a helluva lot cheaper than $100 for a new rotor.  My mantra is when the fault is not obvious to always try the cheap/free stuff first.

OBTW, did you also clean the slip-rings before installing the new brushes?  Could be they are not making good contct due to all the black crap that has built up on them over the eons...

[mtpica]

Update:

After inconclusive results from my troubleshooting procedures (I'll take almost ANY mechanical problem over this doggone electrical stuff!!) I finally replaced one by one, the alternator stator, alt. rotor, diode board, voltage regulator, and starter relay with known good components from the other R65..........

.......and NOTHING changed.  I'm still getting the same softly glowing, sometimes flickering GEN light at higher rpms.

So, I guess its time to go through the harness, beginning with the starter, and clean connectors and contacts, one by one.  

Mark
1982 R65
1984 R65
1981 R100RT

[Chris_in_BC]

Update:
 I finally replaced one by one, the alternator stator, alt. rotor, diode board, voltage regulator, and starter relay with known good components from the other R65..........
.......and NOTHING changed.  I'm still getting the same softly glowing, sometimes flickering GEN light at higher rpms.
T

Mark , you didn't mention whether you are now charging or not. Have you put a voltmeter across the battery terminals, got a reading, then start the bike and check again as you rev?

I have had the flickering gen light before and in my case it was cracked solder on one of the big diodes on the diode board. Hard to see a faint crack line around the diode. Cleaned it up and added more solder. No further problems.

But as you have swapped in all good parts (you checked other bike was charging,eh?) I agree you need to start looking at connections.
But having two bikes it is easy to swap around. How about putting the bad(?) stuff on the other bike and see if the problem shows up there. If it doesn't it kind of implies your parts are still OK, just something funny in the wiring.