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R 50 S Charging issues

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jwonder
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R 50 S Charging issues

Post by jwonder »

I have a R 50 S fresh restoration and when I slightly rev the throttle the charging light goes out. When I rev it higher the charging light flickers. I put both an analog and digital voltage meter on the battery and it registers 6.4 volts DC before I start the motorcycle, 6.5 at idle and 6.7 at higher revs when the light is flickering. This is not close to the 7.2 that is expected.

The components installed are as follows:

1) A new solid state voltage regulator.
2) New brushes.
3) A cleaned up armature of unknown origin as it was removed from the motor and in a box, but I believe it is for this particular motorcycle. I tested the armature and it tested fine. I cleaned the armature segments before installation.
4) A cleaned generator of unknown origin as above and I am not sure if it is for this particular motorcycle. I tested the coils and the resistance tested good.

The generator shows the part number: IJ/CGE 60/6/1700R5 on the case and I see no "Bosch" name on the generator at all.

I am thinking I have a mismatched armature and generator, but I am not sure if that would cause this issue.

From the part number above, it looks like 60/6 would be 60 amps at 6 volts, but that may just be wishful thinking.

It could be a bad voltage regulator, but it is brand new and I would think it would be reliable (hopefully).

Any thoughts are welcome!
James Wonder
Vice President, Vintage BMW Motorcycle Owners
2022 BMW Friend Of the Marque
Long Island, New York

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schrader7032
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Re: R 50 S Charging issues

Post by schrader7032 »

That part number comes upon MaxBMW's site for a /2 era Bosch generator 6V 75W. They have it listed as part number 12 31 8 002 032 but when I try that number on RealOEM it says it's not valid. Maybe it's akin to 12318002032 on the Salis site.

Have you looked through Doug Rincke's book(s)? This probably doesn't translate to the generators, but on the /7 alternator and voltage regulator, there is a way to bypass the regulator to assess the alternator output vs the functioning of the regulator.

I wouldn't rule out the regulator...would be nice to have another known good to check it out.
Kurt in S.A.
'78 R100/7 '69 R69S '52 R25/2
Fast. Neat. Average. Friendly. Good. Good.

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Re: R 50 S Charging issues

Post by jwonder »

Not only did Kurt find it (I can always rely on Kurt), but Chris Shea our wonderful Treasurer also found it and here is the link to the generator I have: https://shop.maxbmw.com/fiche/PartsSear ... 0002%20030.

Now, I typed the number off the body wrong, it is "Bosch LJ/CGE 60/6/1700R5".

I called the most excellent Richard Scheckler on the phone and he gave me some ideas to try so I will be looking at them today and I will get back with any things I find. His first thought was that the brushes might not be riding correctly on the armature, so I will be checking that first.

I will keep this thread up to date with what I find.
James Wonder
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Re: R 50 S Charging issues

Post by chrishea »

Three checks for armatures: each section to ground (should show open), adjacent section to adjacent section (all should be similar resistance and not open), and sections “180 out” (all should be similar resistance not necessarily the same as adjacent and not open).

I was thinking brushes too or spring pressure on the brushes.

Readings are with lights off? Magneto ignition?

Then there’s check the wiring for good connections. Actually maybe check that first!
Chris
Seattle

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Re: R 50 S Charging issues

Post by Slash2 »

Did you replace the springs when you replaced the brushes?
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Re: R 50 S Charging issues

Post by Daves79x »

I had one of the electronic voltage regulators go bad on my R69 after about 100 miles of running. Of course there is no warranty, but another new one works fine. The one on my R50 has 4 years and 2500 miles on it and works fine.

Dave
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Re: R 50 S Charging issues

Post by jwonder »

I have already found 2 problems with my charging system and I will hold the comments for the final report that I will write up.

I would like to know if anyone here knows how to tell a 60-watt armature from a 75-watt one??

I see listings where they are distinguished and others that just list “armature”.

I have 4 armatures sitting in front of me now and 2 look different than the other two.
9C9D07FA-08B8-4B69-BC0D-42E1169AFE0B.jpeg
C6C59CE2-A2BA-4A6B-A8B6-E16759B0EF94.jpeg
C23BA21E-C283-4A76-B740-1C455D47E9D9.jpeg
The two on the right (after you open the pictures) have more and tighter windings and are also wound in a different direction! Hmmm.

The one in the motorcycle is the same as the one on the left and I am quite sure it came with a 60-watt generator.

I would assume the two on the right are 75-watt armatures just by the look of them but I learned not to assume!!!

Guidance is appreciated.
James Wonder
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Long Island, New York

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Re: R 50 S Charging issues

Post by chrishea »

Wow. Didn’t know there were two power ratings.

Have you done any resistance checks? To me, to get more power in a DC generator would mean more windings in the same volume. Same volume and more windings should mean a thinner and longer wire, wound a few more times around, so the higher power rated armature should have a higher resistance. What do the opposite armature segments read for resistance on those specimens?

The direction of the windings shouldn’t matter. They go to the opposite side segments.
Chris
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Re: R 50 S Charging issues

Post by wa1nca »

My 55 R50 should have the 60 watt armature, not sure when bmw upgraded from 60 to 75 watts, don't think is was when the slash 2's evolved
Will get a picture soon
The 4 field coils are also different per Salis site and even the mechanical regulator has different part numbers(I think they are the same but are adjusted to match the 60 or 75 watt armatures)

Have you tried one of the 2 other ones that have different windings with the field coils that you have
Also does your electronic regulator have a adjustment to vary its output
Tommy
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54 R51/3, 55 R50/Velorex 560 sidecar, 64 R27, 68 R69US, 75 R75/6
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Re: R 50 S Charging issues

Post by jwonder »

I fixed the problem!!!!

It was a multi-part issue with very specific issues found and others that I am surmising. I will outline what I did, and learne.
(go to #4 below for the final fix that solved the initial problem I saw):

1) The regulator was not adjusted appropriately. I put my multimeter on the battery and with the motor off (key on) it read 6.2 volts, with motor idling it was 6.3 and maxed out at 6.8 until I adjusted it! This was a brand new regulator and it was not adjusted appropriately. Further, there was no paint on the adjusting screw like all the others I have purchased, so I am not sure of the background of this particular regulator, but it is functioning as it should now. I swapped another regulator in to verify that the charging system would charge to 7.2 before I adjusted the one I had.

2) On the topic of Armatures, having 5 different Armatures to compare and measure is always great. I noticed that the Armature's have numbers on the sides of them (see the pictures below) and that the ones that have more windings, and the others that have less have the SAME main part number on them. Interesting.... Of the Armatures I have here, 4 of them have the number L140/3Z followed by a smaller number that is different and probably a build date. The Armature that came with my R 50 S and that I think is the original 60-watt one has the number 3104 013 403 804 stamped into it. I have no clue how to cross reference these numbers right now.
IMG_7122.JPG
IMG_7121.JPG
3) On the 60 to 75-watt difference, I was told from some people that the 75-watt Armature is bigger in diameter and wondered if I had only 60-watt Armatures. I measured the distance between the coils in the two 75-watt generators I have and the 60-watt ones and the distance (width) between the coils are exactly the same. A larger Armature would not fit. Because of this I decided to go with the Armature with more wire wraps and paired it with my 75-watt generator.

Pairing the Armature with more wire, and the 75-watt generator produced, by far, the most voltage at a much lower RPM than any other combination I used! Voila!

4) Once I had the right Armature, and the right generator paired together I was goo to go, right? NO!!! I still had the problem of the generator light coming back on when I revved the motor. So, idle was a red light, off idle no light and then the light would come back on!

I remember what Richard Sheckler told me, and after emailing Vech, he told me the same thing. The brushes are not riding on the Armature properly!!! So, I began to check that out. I took my dial indicator and mounted it with my magnetic mount (see picture below) and found that I had 0.006" runout on the end of the Armature. I removed it, cleaned the nose of the crank, and then re-positioned the Armature several times until I got a runout of 0.0015". Now, I think I have less than that, but it is hard to accurately read because the indicator goes between the segments.
IMG_7123.JPG
After getting the Armature setup with as little runout as possible, I put the generator back on and tested the motorcycle. I had LESS glow of the red light at high RPM, but it was still glowing slightly! I was on the right track.

5) The last piece of the puzzle is how the brushes ride on the Armature. This could be lack of spring pressure, or in my case the fact that the brushes were sharp on the edges and you could hear them jumping as the edges were digging in. When you watched the brushes with the lights off there were more sparks when the red light was glowing at higher revs. My brushes are new and the edges were sharp.

I removed the brushes and filed the edges flat. I did not file the brush fully flat, just the sharp edges.

I put the brushes back and the red light never glowed again!!!! Now, the brushes still need to be "broken in" so they ride nicely, but a hundred miles of riding will fix that.


So, here are the CLIFF NOTES:

1) Not getting 7.2 volts without headlight on when you rev the motor? Look to the regulator first.

2) I believe (this is my conjecture) that you can identify the 75-watt Armature by the amount of wire and wraps used. Take this for what it is worth.....

3) Make sure the runout on the front of the Armature is as little as possible.

4) Look at the springs and the brushes and adjust as needed.


Any questions please ask, I learned more than I would have thought during debugging this problem!!
James Wonder
Vice President, Vintage BMW Motorcycle Owners
2022 BMW Friend Of the Marque
Long Island, New York

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