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312Icarus
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MY 68 R50 developed a noise this past summer, ( I posted a thread) and I cant find the source of the noise. The engine was torn down 2000 miles ago and had slinger service, new cam and main bearings. In an attempt to forstall tearing it down again, I did a UOA. The numbers for Iron and Copper are quite high, Iron 81 ppm and copper 253 ppm. The noise seems to be coming from the top side (maybe cam bearings or cam gears?). Has anyone else done a UOA and care to post thier results, and do any of the more learned members have a suggestion as to what may be going on?

Thanks for all your help,

Icarus

The Plunger
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Hmm, did lifters(tappets) and

Hmm, did lifters(tappets) and bronze inserts get replaced? You might have a loose or cracked one.

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Brian
'52 R67/2

312Icarus
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Don’t know, I didn’t do the

Don’t know, I didn’t do the work. I’ll check. Keep the ideas coming!

Thanks,

Icarus

Twocams
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Why dont you start taking the

Why dont you start taking the engine apart. Both heads then both cylinders. Take the pan off, have a look see. It has to be done to find the problem and to fix it. I would take it all apart to make sure to replace/fix all the engine problems. But thats me, no sense putting a band aid on it and going in a 3rd time.

twocams

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Twocams
69 R69S 03 K1200GT
92 R100RT

The Plunger
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Years and years ago I rebuilt

Years and years ago I rebuilt a 75/5 and took it for a test spin with my brother. Foolishly, I ended up about 20 miles from home and as I was accelerating up a hill something went bang! Rattle rattle rattle. Took off the valve covers to find that a pushrod was flopping around. I took it out and that sucker limped home on one cylinder! Come to find out the lifter shattered. I picked out the bits I could and honed the insert which wasn't too damaged. We decided to order up a set of HD lifters which was a good thing because upon inspection, two other lifters had cracks. I learned to ALWAYS inspect lifters before reinstalling.

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Brian
'52 R67/2

312Icarus
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^ I am resigned to doing just

^ I am resigned to doing just that, but quite frankly I would like to have a clue before going in. The problem is, pulling the heads and the cylinders and the pan is easy. Guessing it is in the valve train (cam bearings/lifter etc) is a different kettle of fish. I’m a fairly accomplished back yard wrench, but pulling the front end of the engine (generator/mag/cam gears) is a bit more than I am really interested in doing.

Icarus

312Icarus
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Can you get to the lifters by

Can you get to the lifters by removing the barrels?

I once had a vintage 911 Porsche that started clacking and clicking a few miles from home. I tore it down, and found it had sucked a valve and broken a rocker arm. Major pain. Doing vintage 911 cams and chains was a real learning experience

Icarus

Twocams
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Icarus, Sounds like you have

Icarus, Sounds like you have enough skills to take this baby apart. You have the book? You need the tools? and hot plate.
The oil has been threw the whole engine already with all that garbage. You could just fake it, and not take all apart.....but

twocams

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Twocams
69 R69S 03 K1200GT
92 R100RT

312Icarus
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I know I can do it...but I

I know I can do it...but I really don’t want to. Time is an issue this winter for me. I’ve got a nice warm shop, but I lack the pullers, and most importantly, I don’t know what I’m looking for. The noise is so odd that non of those that have heard it can ID it.

Icarus

Twocams
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Nothing strange like the

Nothing strange like the flywheel bolts came loose or Bolt?

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Twocams
69 R69S 03 K1200GT
92 R100RT

312Icarus
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^. The truth is, I don’t have

^. The truth is, I don’t have a clue. The engine started making a rotational noise ~50 miles ago. It is very hard to isolate, evens with a stethoscope. It develops to a high pitched howl at ~2500rpm. My first though was clutch release bearing but since it doesn’t have a conventional bearing, AND it is effected by clutch action I don’t belive that is what it is. As best I can locate by ear is it sounds like it is coming from the top of the engine.

As I said, it just (under 1000 miles ago) had slinger service professionally done along with new main and cam bearings. My current thought is a bad cam bearing. The copper in the oil is interesting, the iron less so. Without a real baseline for the oil analysis it is pretty hard to guess. What major component has a lot of copper in it? (And is ~250ppm a lot?)

Icarus

schrader7032
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Give Vech a call. Ask about

Give Vech a call. Ask about the internal sources for the copper and iron. It has to be a specific item. From my limited experience, the thing with variations in metal alloys would be the bearings. Seems like everything else is aluminum and steel...of course there are alloys included there as well.

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Kurt in S.A.
'78 R100/7 '69 R69S '52 R25/2

The Plunger
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Copper?

What major component has a lot of copper in it? (And is ~250ppm a lot?)

The only items I can think of internally with high copper content are the lifter bushings. Are the rods bronze?
You might try running the motor up to temp and then using a precise digital thermometer check the immediate area above each pushrod gasket for a spike in temp.

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Brian
'52 R67/2

miller6997
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What kind of noise?

Can you describe the noise in more detail? Does it go away after the engine has run for a minute or two? For half a century, my R69S has made a howling sound soon after startup that goes away as the engine warms up.This happens more than half the time. BMW technicians have told me that it's a common noise and nothing to worry about.

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Jon Miller
'67 R69S
'13 F800GT

312Icarus
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I did call Vech, and he said,

I did call Vech, and he said, “If it makes a noise it didn’t before...tear it down!” Good advice ultimately. What I’m trying to decide is, do I pull the engine or can I start with something else.

As for the lifters...? (Apartently some engines have bronze connecting rod bushings, not necessarily BMW engines)

As for the sound, it is a regular, rhythmic sound at idle, not grinding or knocking, a rotational noise. At speed it has a high pitched howl. I did post a link to a YouTube video on another thread here. I will try to find it and repost the link.

Thanks again

Icarus

Here is the link to the thread with the video link.
http://www.vintagebmw.org/v7/node/14507#comment-45898

Twocams
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I was checking Max BMW parts

I was checking Max BMW parts list. R50 shows your engine having 2 crank bearings 6207 front and rear. Lots of brass there.
Front main bearing on my R69S (6207) the other bearing is my rear main. Not used on yours. Just for your information.

twocams

  • dsc00003.jpg
  • bmw_case_and_crank_003.jpg
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Twocams
69 R69S 03 K1200GT
92 R100RT

312Icarus
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^. that is sort of what I

^. that is sort of what I was thinking...wondering if the cam bearings have the same bronze cage system. I know my guy mentioned that he has seen bad cam bearing right out of the box.

Icarus

wa1nca
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Camshaft bearings

They have a steel cage

Tommy

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54 R51/3 55 R50 64 R27 68 R69US 68 Sears Allstate 250 (Puch)

312Icarus
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Thanks Tommy...and

Thanks Tommy...and all!

Icarus

wa1nca
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rotational noise

I also had a rotational noise on my r69
My charging system stopped working
I replaced the armature and it fixed my charging problem and to my surprize the rotational noise also went away

Always need to do the easy things 1st
To disable the generator output you can pull one of the generator brushes
It also could be the field windings are touching the armature causing a similar noise
I would also pull the field windings and see their no shinny marks indicating that the field coils may be touching the armature
Just a couple of wires and 2 allen screws to remove to field windings and no need for the armature puller bolt to do this

Tommy

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Tommy Byrnes
54 R51/3 55 R50 64 R27 68 R69US 68 Sears Allstate 250 (Puch)

wa1nca
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rotational noise

I also had a rotational noise on my r69
My charging system stopped working
I replaced the armature and it fixed my charging problem and to my surprize the rotational noise also went away

Always need to do the easy things 1st
To disable the generator output you can pull one of the generator brushes
It also could be the field windings are touching the armature causing a similar noise
I would also pull the field windings and see their no shinny marks indicating that the field coils may be touching the armature
Just a couple of wires and 2 allen screws to remove to field windings and no need for the armature puller bolt to do this

Tommy

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Tommy Byrnes
54 R51/3 55 R50 64 R27 68 R69US 68 Sears Allstate 250 (Puch)

312Icarus
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Thanks, Tommy, That is in

Thanks, Tommy,

That is in fact the first thing I thought of, and indeed the first thing I tried! (To no avail!)

Icarus

Danedg
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Your rocker arms have

Your rocker arms have sintered bronze bushings as well as the small connecting rod bushings. The rocker arms can make a lot of noise when loose.

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'54 R51/3, '65 R60/2, '69 R60/US, '95 Mystic, 74 MG Eldorado

312Icarus
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Mystery solved...we hope. It

Mystery solved...we hope.

It turns out that the left side wrist pin bushing was siezed. Scored the pin, (probably caused the high iron content in the oil as well?) but the piston seems fine. Doing new bushings on both sides. Now the $64,000 question is, what do you all think might have caused this?

Icarus

MikeL46
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Improper fit when assembled?

Improper fit when assembled? Too much or too little clearance, or maybe no lubricant during assembly?

Mike

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67 R50/2 w/R100 engine/trans and Ural Sidecar
69 R60/2 76 R90S 78 R100RS
70 Triumph w/Spirit Eagle Sidecar

312Icarus
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^. Or, or, or...twisted or

^. Or, or, or...twisted or bent rod, or just plain bad luck?

(Thanks for the hints folks!)

Icarus

808Airhead
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High miles and revs? These

High miles and revs? These bushings are a weak spot...

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Thomas M.
R69s - R60/2 - R67/2 - R51/3

312Icarus
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Probably not Hi Revs I have

Probably not Hi Revs

I have tended to run this bike pretty gently, especially since it was rebuilt. 60-65mph is pretty damn fast for these old guys (the bike and me!). Might be high miles, ~50,000 total miles. I don’t think we did rod bushings when we did the slingers.

Icarus

312Icarus
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Up date...

So, put back together, and guess what? It still makes the sound! Seems like the rod bushing was just an ancillary issue. We are going to take the engine out, tear it down. Now suspecting either a oil slinger rubbing or possibly a bad cam bearing (even though they only have a couple thousand miles!). Oh well, only time and money!

Icarus

Twocams
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Drat, that sucks to tare it

Drat, that sucks to tare it all down. Always think the worst,then your surprised when it just a $10 part. I think thats the right saying?

twocams

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69 R69S 03 K1200GT
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312Icarus
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It is what it is...

It is what it is. We will see what it turns out to be. I don’t think it is something “expensive” just some thing amiss. The bitch is the time involved. That said, the dead of winter is the time for shop work.

Thanks all for the advise and encouragement. I’ll post when new info becomes available.

Icarus

Daves79x
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My Front Slinger

When I rebuilt my R50 last winter, the front oil slinger rubbed on the case/bearing holder (whatever is right there to rub on). Made quite a racket when turning the crank over by hand. With just the crank in, I was able to pry the slinger away from the block enough to clear the interference. You might check that after everything is out but the crank. I understand with replacement slingers this is a common problem. Hope you find it!

Dave

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312Icarus
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Worse than expected!

Well...the verdict is in. Seems that the one rod throw is very loose. I’m going to send the crank out to be rebuilt (big $$) and bite the bullet and rebore to first oversize and put new pistons in as well. The cost is large, but as my wife suggested, that in 40 years of ownership, and 50,000+ miles, besides oil changes the bike has cost me nearly nothing, so the cost per year is pretty small.

It has been suggested that the bike got very hot at some point (not that I remember) but going forward, I sure need to find a way to not get it hot in the future.

Icarus

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