The New And Improved Unofficial R65 Forum V2
Technical Discussion => BMW Technical Q&A, Primarily R65 => Topic started by: dewane on August 26, 2010, 09:46:14 AM
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I have an '83 R65. Got a new dynacoil to replace the cracked original coil. Had the gen light go on dimly, so replaced the diode board and checked all wires and shot some contact cleaner in the connections.
That worked for all of 100 miles. Now the gen light doesn't go on when I turn on the key. Can you let me know of likely culprits, and ways to check? I'm sure this is here somewhere.
Thanks
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Seeing as how you were just in the area doing some work, I would go back and recheck the connections, something may have just become disconnected.
If everything checks out, then you need to do a little trouble shooting .
First, I would check the light bulb, they don't go bad too often, but not difficult to get to, unless you have a fairing, it's what is commonly called a 'wedge' type bulb, it sits in a socket, doesn't lock into the holder, not a great design for this application, bulb may may come out of it's holder.
The bulb is a common SAE 168 or 194, available at most auto parts stores, don't get an LED replacement bulb, the charging system won't work correctly with one installed .
Second place to check, is the alternator rotor, an 'open' rotor will cause the 'GEN' light not to come on .
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Everytime on I have had the Gen light is dim it has been brushes needed replacing or not contacting or bad contections with the voltage regulator harness or some of the contectors at the alternator.
Don
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Along with the possibility of sketchy connections on the other side of the bulb (going to voltage regulator and from there down to the alternator) you could also have a corroded contact in your ignition key switch or on the terminal from that switch that feeds the bulb/v-reg/alternator branche of the circuit.
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... don't get an LED replacement bulb, the charging system won't work correctly with one installed.
An Led GEN light most certainly will work if you also fit the Generator Light Auxiliary Circuit.
http://www.motoelekt.com/genlightacc.htm
I have this setup on my 1981 R65 and it functions just fine.
Monte
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... don't get an LED replacement bulb, the charging system won't work correctly with one installed.
An Led GEN light most certainly will work if you also fit the Generator Light Auxiliary Circuit.
http://www.motoelekt.com/genlightacc.htm
I have this setup on my 1981 R65 and it functions just fine.
Monte
Now that is an idea! What are the part numbers for the LED bulbs? I hate diging into that instrument.
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If they are available at your local auto parts store, they are the same numbers as the incandescent bulbs, 168, 194 .
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Radio Shack gots 'em.
(https://bmwr65.org/smf/proxy.php?request=http%3A%2F%2Fi196.photobucket.com%2Falbums%2Faa1%2Fmontmil%2FBMW%2520R65%2FDSCF0002_1.jpg&hash=90c9f0793a5447961aa4f5f83ca865bac2e762d7)
Monte
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I think Bill was looking for a direct replacement bulb .
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I think Bill was looking for a direct replacement bulb .
:-/
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I've tried the LED replacement bulbs in the instrument background lighting, high beam indication and turn directional indication, they were not suitable for any of the uses on an R65, just too dim compared to an incandescent bulb .
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Hey guys, if we could get back to my problems, which naturally are the most important things...heh
The gen light is not dim, it is off. I pulled the tank (again) and checked the wiring (again). all wiring in the alternator area there looks fine. Pulled the diode board (again) and checked the wiring there.
The light is fine, I swapped the gen light with the oil light and that is not the problem.
Can you let me know how to do a continuity test for the alternator?
I'm normally a pretty patient guy when it comes to wrenching, but looking at the wiring job that somebody did under the tank just makes me mad. They routed the throttle cable like a preschooler would do, and wires go every which way with no sense to the routing they would take as a matter of common sense.
I had a slash 5 and the alternator went out and I swore off German bikes for a while. If this one is out, it's "cut bait" time.
Then again, I think I'm feeling like my friend says when he's working on something and gets a problem: "you want to buy this truck for 10 bucks?" "why what's wrong with it?" "this bolt won't go in right".
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To check the continuity of the rotor with it still installed, you need to raise the brushes and place a piece of paper between the brushes and the slip rings .
With that done, you need to place the test leads from a multimeter one on each slip ring, with the meter set to the ohms position a good rotor should read a couple of ohms, can't remember the exact value right now .
A faulty rotor would read 'open', no continuity .
We were just killing time until you got back !! [smiley=1drink.gif]
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Hey, thanks!
I blew a fuse in my multitester. So I just shorted those two brass rings, per another thread I read. And, the gen light goes on.
Would that indicate a bad rotor as well? I need to go to the store and get a fuse anyhow
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When you touch a metal object between the slip rings with the key in the on or run position, you are testing the wires from the brushes all the way up to the light bulb .
Seeing as how the light goes on when the test is preformed, the wiring is good .
So now you need to check just the rotor, that's why you need to insulate the brushes from the slip rings .
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OK thanks. I found some fuses in my toolbox (it's a really weird, reall low amp fuse) and checked it out.
Reading is an open circuit. Note: I got the same reading when I disconnected the two spade terminals coming from the brushes. When connected, ohms reading is about 1.5 ohms. I did the paper thing as well - same reading - open circuit.
So...bad rotor? On the good side, I'm doing this before going on a long trip. So, best for it to happen now, I guess.
If so, should I call up Rick from motorrad? Or where can I get a good rotor.
Also, anything unusual to note about removal-replacement? I see from the Haynes book that I need to insert a rod into the rotor bolt hole after removing the bolt?
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To remove the rotor you need a special tool, it's available from Motorrad Elektrik for about $5, don't try inserting a rod or anything else, chances are good it will bend and get caught in there, a real job to get it removed .
Motorrad Elektrik is about the best place for electrical parts here in the US .
If you've done business with Rick Jones, you already know he's a great source of parts and troubleshooting help .
How do your brushes look ?
New brushes are about .75 inches long, so if their on the short side ( when they get to about .25 inches long, they start giving you problems), you may want to consider replacing them now as well .
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Rick is a great help for sure, and nice to have somebody around to help to keep these old bikes on the road. Thanks a lot for the info Bob - if you're ever in the SF Bay Area, I owe you a cold soda, or oat soda (my uncle's name for beer ;D).
Dewane
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Hey guys, if we could get back to my problems, which naturally are the most important things...heh
OK, newbie. Consider us adequately chastised. [smiley=furious3.gif]
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Umm, when you measured open circuit, you were measuring with the probes on the slip rings (copper rings on front of alternator) with the brushes disconnected or with business cards/plastic sheet inserted between the brushes and the rings, correct?
If your multimeter is no an autoranging type - be sure that you had it set on the LOWEST Ohms setting (usually 200 Ohm full scale) as the alternator is very low resistance (normally). On out of range display measurement might look to some people like an open circuit..
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might look to some people like an open circuit..
Short circuit?
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Umm, when you measured open circuit, you were measuring with the probes on the slip rings (copper rings on front of alternator) with the brushes disconnected or with business cards/plastic sheet inserted between the brushes and the rings, correct?
If your multimeter is no an autoranging type - be sure that you had it set on the LOWEST Ohms setting (usually 200 Ohm full scale) as the alternator is very low resistance (normally). On out of range display measurement might look to some people like an open circuit..
Thanks for the info. I did both actually - tried it with the brushes disconnected, and then with paper between the brushes and the slip rings. I figured it was the same but...well why not?
With the tester, I did it with both settings, which on mine is "Rx10" and "Rx1k" settings. It's an old analog one - I like those better than the digital.
Is there any trick to moving the brushes out of the way? I can't get a good hold on the spring loaded clips that hold them in, especially that one in the rear. The Haynes manual says "see illustration" and then they don't show much of anything in the illustration.
There is open circuit, closed circuit, short circuit. Basically a short circuit means the juice is not going where it should - electricity always takes the shortest route, so it's taking a shorter path. In fact, that's exactly what I did when I did the test by shorting the slip rings together and turning the key, and got the gen light to turn on, as a test.
Which one is this? Open I believe, a short would mean that the circuit is complete, and I don't believe it is.
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I would slip a 3X5 card in between the brushes and the ring...mo rigid! ;)
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Hey, thought I'd follow up on this. I got a new rotor from Rick at Motorrad and installed it. His pilot-puller tool to pull the rotor worked perfect - worth the six bucks or whatever I paid for it. Popped in the new rotor and all is well.
For some reason, it even runs a lot better - i rebuilt the cards and replaced the coil with a Dynacoil, and reset the timing (it was way off), but seems like it just runs a ton better with the new rotor. That...makes no sense. I was getting about 30 mpg before and after all my fixes, I'll be interested when I need to refill what I'm getting now. It will probably be 30.
Keep em on the road!
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Glad to hear that the R65 is happy again!
Properly tuned up and ridden at relaxed pace, you should get~45 MPG (US Gallon) or so. I've gotten as high as 49.5 toodling at 50-55 on secondary roads and as low as 39-40 (running ~ 75 MPH steady, loaded, on interstate highway and up&down big hills).