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R75/5 Charging issues

I think the rotor is mounted properly. I used a new bolt and tightened to spec. The wobble almost completely goes away at rpm above idle. But check out the pic, looks like a leak behind the timing cover, could that be the front seal and related to this?
The bike as verified 45k miles. I have the original owners manual with maintenance records back to day 1. I picked up the bike in September 2017 after it had not run much in 20 years and did the usual (main engine seal, push rod seals, forks, etc.). It also needed a head bolt helicoiled in.
 

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If there is play in the front main bearing it would allow the wobble. And if indeed the entire nose of the crankshaft has play in the bearing then that could damage the seal.

But, and this is a very big one - how bad is it and does it warrant tearing the engine down to bare case to fix it?

If it seems to only wobble at idle and the seal seeps a little it may not be worth a tear down yet.
 
Just curious

I am just curious.

If you put the old rotor back on, does it wobble? I know you said it was shot, so it may not charge. If it does not wobble you know the new rotor is bad. If it does, well that might be a big problem.

You should not have to run the bike all that long a period of time to see if there is a difference. Good luck. St.
 
anotherbmw said:
I think the rotor is mounted properly. I used a new bolt and tightened to spec. The wobble almost completely goes away at rpm above idle. But check out the pic, looks like a leak behind the timing cover, could that be the front seal and related to this?
The bike as verified 45k miles. I have the original owners manual with maintenance records back to day 1. I picked up the bike in September 2017 after it had not run much in 20 years and did the usual (main engine seal, push rod seals, forks, etc.). It also needed a head bolt helicoiled in.
Click to expand...

Hi Olaf,

Some observations and thoughts follow.

1. The leak around the inner timing cover is due to a leaking inner timing cover gasket, not a leaking crankshaft seal. The cavity behind the inner timing cover is oiled all the time by the oil pump high pressure relief valve, so it's not an oil free cavity. That seal is heat activated
a. If there was any oil on the engine block or the inner timing cover mating surfaces, it will leak.
b. If the bolts that secure the inner timing cover were not torqued correctly, the seal can leak.
c. If the inner timing cover mating surface is nicked or warped, the seal can leak.

2. The crankshaft nose bearing could be failing. If so, that's a fairly easy fix. (Also, see #5 below). And, this bearing is NOT the front main bearing. If that's shot enough to let the rotor wobble, you will have a great deal of engine vibration and will quickly damage the crankshaft journal.
--> 1983 BMW R100RS Install Inner Timing Cover

3. The rotor is locked onto the crankshaft taper NOT by the bolt but by completely oil free, clean tapers on the crankshaft and the rotor. You can see what the difference is between a slightly oily taper and an oil free one here (go to time 15:23):
--> https://youtu.be/b-4B0O6P5b0?t=923 (go to time mark 15:23)

4. As I looked at your video, it appeared to me that the rotor was not centered on the crankshaft taper, but that could be an illusion due to the angle. If so, it's possible that the rotor is loose on the taper (see #3 above), a failing nose bearing (see #2 above) or the hole in the rotor is off-center (not likely as it seems to smooth out at higher RPM).

5. You said you "did the usunal (main engine seal ..,". Was that the front main seal, the rear main seal, or both?
a. If it was the front main seal, then you were inside the inner timing cover where the timing chain is located. So the crankshaft nose bearing had to be disturbed. If you didn't get that bearing installed correctly into the bore in the inner timing cover, perhaps that's the problem. See #2 above.

6. I would NOT ride this bike until the problem is found.

I hope this is helpful as you dig into this problem to find the cause.

Best.
Brook Reams.
 
As always, great info, thanks to y'all. I'll try to answer your questions:

PGlaves, I don't think there is play, but not sure how to test. I can't feel any sideways play, but wasn't really expecting it.

Steven, I have not tried to put the old rotor back on, but probably want to try that, just to be sure it's not the rotor

Brook,
1.) I see. I never had that timing cover off.
2.) Honestly, I have not a lot of engine vibration so that should be a good sign I guess. I will watch that video.
3.) Yes, I had watched that video of yours on the EME site. I think I installed it correctly but who knows!
4.) I am pretty sure the rotor sits solid on the taper. I took good care, followed your video, wiped it with alcohol, used a new bolt and torques to spec.
5.) Rear main engine seal only. I did not touch the front.

Here is what I think I am going to do:
a.) make sure rotor sits correctly on the taper
b.) if it does, remove EME system and install the old rotor, stator, stator cover and brushes (no wiring needed I guess) to compare
c.) if there is no wobble with the old rotor, I assume something is going on with the new rotor, if there is a wobble as well, it sounds like it could be a failing nose bearing.

As always, I will report back. Thanks everyone!
 
Brook is the man

I am very interested in what you find.

If in your assembly of the old rotor and such, the problem still exists, Brook is the man to listen to.

I feel for you, I hate when I do something to improve or fix something only to have something else go wrong. You have been through the ringer with the short due to the bad insulator, now this. In my garage, the air would be shades of blue by now. St.
 
From the video it seems to me that the head of the bolt and the hole of the rotor are not centric to each other. At one spot the head of the bolt seems to be closer to the edge of the hole than to the rest.

For the test I would just swap the rotors and keep the new stator.

With the rotor removed you could check the nose of the camshaft for centricity (sp?) by using a measurement tool setup like this:

DSC02256sm.JPG

/Guenther
 
Guenther, that's a good idea and I even have that instrument, but as you can see in the videos below, detailed measuring won't be necessar IMHO. But one step at a time:

First, when I removed the new rotor I realized that the bolt, which I purchased new with the unit, was wobbling when turning it out, look at the first video. I tried with the old original bolt and there was much less wobbling.

But I really think the issue is with the rotor. The 3rd video shows the bike running at idle in slow motion with the new EME rotor, still the same issues. I then removed the new rotor and put the old rotor back in. Runs as smooth as it should, IMO.

1. Removing the new bolt:
https://drive.google.com/open?id=1F6i-vA9zd5aZB-hWx4LmKDJBXpPgGWfO

2. Trying with the old bolt, seems straighter, wobbles less
https://drive.google.com/open?id=11iShutxEHz2hgyTsmfhjDtS0ywfEq_FO

3. New EME rotor, wobbling
https://drive.google.com/open?id=1Dg8jPJ2OtMIi_jhFzKVanF9jeXPofhsr

4. Old rotor is very smooth
https://drive.google.com/open?id=1WEE2JjGwVDYGybKmMXzZjac45w_GbGvl

I will also reach out to EME and see what they say.
 
Ene

Very good they are standing up and doing the right thing for you.

Always best to use a trusted, long established vendor for our parts and accessories.

I can't wait to see how this turns out, gives me some excitement in my dull life without bars and restaurants, school and such. LOL. St.
 
I think you'll almost always find that the vendor, in this case EME, will respond positively to any consumer problems. It's just plain business sense! The quick, positive response people get praised at every campfire that I've been at.
The others? I'll go no farther....
 
STEVENRANKIN said:
Very good they are standing up and doing the right thing for you.
Always best to use a trusted, long established vendor for our parts and accessories.
I can't wait to see how this turns out, gives me some excitement in my dull life without bars and restaurants, school and such. LOL. St.
Click to expand...

1074 said:
I think you'll almost always find that the vendor, in this case EME, will respond positively to any consumer problems. It's just plain business sense! The quick, positive response people get praised at every campfire that I've been at.
The others? I'll go no farther....
Click to expand...

I agree, no compliant there. Although two separate issues with one purchase, that's a bit more than what I would expect. I'll keep y'all updated!

On another note, I see that some of you on this thread are from the Denver area. I plan on riding my GS LC over there in early July and do some of the COBDR. I would be glad to repay the advice I received in form of beer or any other beverage of choice. :) Riding the COBDR should be exactly what the doctor orders in terms of social distancing!
 
You won't have to wait very long. Work is slow and the new rotor arrived today, so I am hoping to tackle this later in the day.

But first I will practice some social distancing, which means riding my GS alone in the green air. (green from oak and cedar, not the virus :) )
 
Finally! New rotor mounted and everything looks great! Charging at over 14V, and the bike has to idle around less 1000 rpm for the charging light to come on, so I am good now!

https://drive.google.com/open?id=14RfMJz4BcdsZZDqy_u8bn39bq_GAQduF


Although here comes the next problem, the carb was leaking so I took the bowl off and the float just went down all the way, basically hanging vertical, and the needle fell out. How can that be? Floats are new and when I mounted them a couple months ago, all was fine. WTH? Also the bike doesn't rev up probably, but I assume that has to do with the fuel situation in the carb. Or I pinched the condensor wire....enough for today and time for another beer.
 
Comparing the recent video with the previous one with a new rotor it looks like the newest rotor sits deeper in the stator. Look at the amount of the outer slip ring visible. Just my curiosity...

Where's the pin that holds the float needle?

Test that the float needle actually closes (with the pin in place!).

Put it all together except the bowl. Then blow into the filler of the bowl while pressing the float up to close the float needle. Does that feel air tight?

/Guenther
 
Guenther said:
Comparing the recent video with the previous one with a new rotor it looks like the newest rotor sits deeper in the stator. Look at the amount of the outer slip ring visible. Just my curiosity...

Where's the pin that holds the float needle?

Test that the float needle actually closes (with the pin in place!).

Put it all together except the bowl. Then blow into the filler of the bowl while pressing the float up to close the float needle. Does that feel air tight?

/Guenther
Click to expand...

Good eye, it sits deeper indeed. I think they sent me an upgraded version. Both brushes are sitting fully on the rings though, but towards the edge.

What do you mean with "pin that holds the float needle"? Do you mean "pin that holds the float"?

Ok, I will try that, thanks.
 
Upraded or properly made

Well, congratulations on solving the charging issue.

If things had been proper, you would not have had it at all.

A properly assembled stator cover/brush housing would have meant no short causing the original problem.

A proper rotor would have been nice as well.

I guess, you just happened to have the stars align in the wrong way for this job. Thank goodness, they are back to normal.

You are getting good advice on the carb, so I won't add to it. Good luck with that now. Cheers, St.
 
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