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Question on Charging system

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jwonder
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Question on Charging system

Post by jwonder »

Hello, I am trying to figure out why my new R51/3 is not charging the battery and I am starting to run some diagnostics. I got the "understanding and maintaining the BMW /2 electrical system" paper and was about ready to start diagnosing when I got to the part of trying to measure resistance from D+ to F-. The picture in the paper and my regulator look completely different and I am sure I have an older version. What I THINK is D+ and F- measure out to be .7 Ohms, not 2.5 to 4 Ohms. I wanted to check to see what others thought and have pictures below of mine.

Any help is appreciated!

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James Wonder
Vice President, Vintage BMW Motorcycle Owners
2022 BMW Friend Of the Marque
Long Island, New York

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wa1nca
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Charging system

Post by wa1nca »

Hello, I am trying to figure out why my new R51/3 is not charging the battery and I am starting to run some diagnostics. I got the "understanding and maintaining the BMW /2 electrical system" paper and was about ready to start diagnosing when I got to the part of trying to measure resistance from D+ to F-. The picture in the paper and my regulator look completely different and I am sure I have an older version. What I THINK is D+ and F- measure out to be .7 Ohms, not 2.5 to 4 Ohms. I wanted to check to see what others thought and have pictures below of mine.

Any help is appreciated!

I think I have the older regulator in my r51/3
I will check tomorrow

Did it ever work or just stop charging?

The D+ terminal is one of the yellow wires coming out the field coil and is connected to the top brush and also to the blue wire for the charge light
The other yellow wire is the Field wire going to the regulator

The low reading you are getting is because the commutator and charge light is in parallel with this and at least one of the field windings needs to be disconnected


The statement to measure resistance from D+ to F is misleading as it does not say to separate one of the field wires (it is assumed that you allready have the field coils are out of circuit and to be tested only with no parallel resistance

I will verify this tomorrow

To bypass the regulator you can disconnect the field wire to the regulator and ground it and the charging should put out max voltage



looks like your regulator is cooked and the burn spots on the commutator indicate the that you may have a bad armature The test from "understanding and maintaining the BMW /2 electrical system" only shows the commutator is not shorted to the armature and between each segment on the commutator is .1 ohm not 0 ohms

If your brushes are in good shape and the regulator is bypassed and passes the commutator test then its likley you still may have a bad armature

This only be tested by a Growler which introduces a magnetic field into the armature to see the current is not shorted to the outside of it and going only to the commutator contacts to produce a output to the regulator and then to the battery and load

Any good electrical shop should have one
Sadly most don't today as it is a plug and play world

I do have one and can test the armature if needed
Phone
413 628 3958

Tommy
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Tommy Byrnes
54 R51/3, 55 R50/Velorex 560 sidecar, 64 R27, 68 R69US, 75 R75/6
Ashfield, Ma
USA

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jwonder
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Thank you!!

Post by jwonder »

I am going to keep testing the system and am learning all about the mechanical regulator. I will be an expert by the time I am done. Thanks for your help and wisdom!!!
James Wonder
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808Airhead
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Clean the points,and with key

Post by 808Airhead »

Clean the points,and with key on play with the points and see if the charge light illuminates,make sure you see the charge /field light working. I had a same old regulator setup on my 1951 R51/3 and after playing with it for hours,taking it apart,cleaning it up,playing with points adjustment,I gave up on its 50+ year old headaches and bought a electronic regulator from Germany for around 80 bux and it is wonderful. I have the same regulator in my R69S,and it fits,easy to install and works perfectly.
Thomas M.
R69S - R60/2 - R67/2 - R51/3 - R69

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Micha
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Same here. Bought my charging

Post by Micha »

Same here.
Bought my charging system over at powerdynamo, and since then never looked back.
Michael Steinmann
R51/3 1952
Engine Nr. 529466

jimstravlin
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Benchmarkworks 12 volt system

Post by jimstravlin »

I have to say that the 12 volt charging system from Benchmarkworks is a real bullet proof system and I have installed it on 90% of the bikes I have restored from a 1952 R51/3 to the 1969 R69S and never had a problem. Hardest part of the installation and the part of the process that takes the most time is changing out all the bulbs to 12 volt...I am a fan...

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Charging system works!

Post by jwonder »

I wanted to update you all on the charging system. Following is what I did:

1) I purchased the Doug Rinckes book off lulu.com and I can say it is a great reference.

2) I cleaned the commutator with light scotch bright and some electronics cleaner. I really only needed the cleaner as it was dirty, not burned.

3) I set the point gaps on the regulator exactly as he outlined and learned more about how the thing functions.

4) I started it and adjusted the no-load voltage to 7.9volts as instructed.

5) I ran all the tests he listed and the only one I am out of specification on is the cut-in voltage. I am a bit high at 7.2-7.4 volts but its hard to tell exactly by watching two multimeters. I am just a bit above spec here and figured I would leave it alone and not play with it.

6) I tested the load voltage and it is all in specifications

7) I forgot about buying an electronic regulator, for now!

I have not ridden the motorcycle (see my other thread) yet but I do not see as I will have any issues.

So far so good.... No on to the cylinder!

James

James Wonder
Vice President, Vintage BMW Motorcycle Owners
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Long Island, New York

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Charging system

Post by wa1nca »

Nice work
Tommy
Tommy Byrnes
54 R51/3, 55 R50/Velorex 560 sidecar, 64 R27, 68 R69US, 75 R75/6
Ashfield, Ma
USA

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Another issue!!

Post by jwonder »

Last night I had the R51/3 out for a ride and the charge light went on and the battery went close to dead after 30 minutes getting home.

Sadly, I am done with the mechanical regulator and a new electronic one is on its way!

While I was checking everything I took everything apart to test and I found that there are several armature segments that look like they have contacted the fields magnets (or had been dropped on the floor) at one time. The small segment on 2 or 3 of the armature segments are moved (see picture). I measured the resistance and every thing seems to be in order and nothing seems out of spec but I wanted to ask the group your thoughts on the damage to the armature segments.

Any help is appreciated!!!!

Thank you!!!
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James Wonder
Vice President, Vintage BMW Motorcycle Owners
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Long Island, New York

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armature damage

Post by wa1nca »

was the armature seated properly did it pop off when you removed it
looks like damage was caused by it was rubbing on one or more of the 4 field coils
check that the field coils are not loose and are parallel to each other
you should see the one or more of the field coils also have wear marks

I would say the armature is junk at this point and now would make sense to upgrade the charging system
the cost of a new armature and replacement field coils would justify a overhaul

worst case the front crankshaft bearing is also bad or the crankshaft has excessive runout but think you should have heard some noise while driving

Tommy



Tommy Byrnes
54 R51/3, 55 R50/Velorex 560 sidecar, 64 R27, 68 R69US, 75 R75/6
Ashfield, Ma
USA

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