The New And Improved Unofficial R65 Forum V2

Technical Discussion => BMW Technical Q&A, Primarily R65 => Topic started by: John M on December 11, 2011, 08:38:41 AM

Title: metallic screaching sound on cold start -up
Post by: John M on December 11, 2011, 08:38:41 AM
cold weather (-2 celsius ) started bike got a sound I can best describe as being like a worn out water pump on a car. the sound came and went through 10 min of riding. Also I noticed some drag in the transmission when in neutral and releasing the clutch lever ( the bike edged forward slightly )
Title: Re: metallic screaching sound on cold start -up
Post by: montmil on December 11, 2011, 09:31:37 AM
I would first do an inspection and/or adjustment of the clutch cable; although the ,"when in neutral and releasing the clutch lever the bike edged forward slightly," is worrisome.

The "screeching" might be a throw out bearing gone bad.

If you have a mechanic's stethoscope -or a l-o-n-g screwdriver- you may be able to locate the source of the noise and better troubleshoot the issue.

Monte  

Title: Re: metallic screaching sound on cold start -up
Post by: tvrla on December 11, 2011, 10:30:54 AM
I suspect the throw-out bearing. It's possibly not rotating as it should (due to cold stiff oil) in the bore and the screeching is the end rubbing in the spring (or whateve that part is it lands in).
Title: Re: metallic screaching sound on cold start -up
Post by: Bob_Roller on December 11, 2011, 11:33:20 AM
In cold temps with heavy gear oil in the transmission, with the bike on the center stand and the rear wheel off of the ground, the rear will will rotate in neutral with the engine running .

If you don't find anything with the clutch rod/throwout bearing, a slight possibility of the starter gear not returning all the way when the starter shuts off .
Title: Re: metallic screaching sound on cold start -up
Post by: John M on December 11, 2011, 12:05:12 PM
Thank you all for your suggestions, the clutch throw out bearing was not something that occurred to me as a possibility. the starter gear not pulling back fully was something I was considering. What really spooked me was the slight tug I felt when releasing the clutch lever when in neutral ( this occurred several times ) That said problem inside transmission to me ( the bike is a 1986 with 92k km on it and it is without the circlip on the output shaft ) I plan to drain the tranny oil for inspection even though it has only been in for 3 months , and proceed from there also looking at the other suggested items . I have been preparing for the eventuality of getting the transmission rebuilt, however it may be a little sooner than I had anticipated. I think I jinxed myself only a week prior when speaking to a friend in the vintage club about how beautifully the bike was running and I had just finished installing a 4 piston front brake caliper from a 1999 oilhead and was going out to test it and bed in the pads when the racket started, the caliper by the way is a great upgrade from the 2 pot Brembo.   Best Regards John Muir
Title: Re: metallic screaching sound on cold start -up
Post by: tvrla on December 11, 2011, 01:29:50 PM
John - some info, please, on the caliper swap! Was an adapter bracket needed, or just shaving the mounts a little?

You don't think you can just waltz in here with a statement like that and leave quietly, do you???

What weight oil are you running in the transmission? Even if it's the correct weight for the temp, it's possibe it just got so stiff from the cold that some of the forces from the input showed up at the output.

Another possibility is the throwout bearing is hanging up in the bore. That's also a common problem - especially on the newer 100GSs. It's made of a plastic material that swells a little and hangs up in there. Don't buy a new one, it'll just do the same. Instead, carefully sand down the diameter until it's smooth in the bore. Frankly, I think that's your problem.
Title: Re: metallic screaching sound on cold start -up
Post by: John M on December 11, 2011, 02:11:21 PM
If you have the 2 pot brembo calipers with 108mm spacing between mounting bolts o.c. then the early oilhead brembo 4 piston calipers bolt on directly they give you more than 50 % more swept area on the disc and in my case give more feel at the lever. the calipers need a little aluminum shaved off so that they center perfectly on the disc.I was able to do the metal removal with my woodshop tablesaw by clamping the caliper to the fence raising the running blade slowly into the mounting lugs ( using an 80 tooth carbide blade ) thus avoiding the cost of a machinist.   In my case the amount of metal removed was 4.7 mm
You have to test mount the caliper without pads to determine the correct amount of metal to remove. Snow Bum writes about this conversion
Title: Re: metallic screaching sound on cold start -up
Post by: lodekka on December 11, 2011, 02:49:14 PM
Is the noise similar to that of mine which is on: - You Tube  - BMW motorcycle R65 engine squeal. I fitted a new plastic bodied bearing assembly and clutch rod prior to this noise starting. I did release the clutch arm, partially withdraw the rod and then start the engine but it still made the noise. If it is the Plastic housing OD then I might just pluck up the courage to do it this winter as the bike has been laid up a year a I thought I had a major engine strip on my hands so other work took preference.
Title: Re: metallic screaching sound on cold start -up
Post by: John M on December 11, 2011, 07:01:36 PM
the squeal you posted on youtube sounds identical to what I have, I hope others will listen to the video and give their opinions
Title: Re: metallic screaching sound on cold start -up
Post by: tvrla on December 11, 2011, 07:39:14 PM
Could you post a link to the youtube screech?

if the throwout was partially disconnected, it doesn't sound like the problem.

Can you tell which end of the engine the sound comes from?

Ok, I found the video:

http://www.youtube.com/watch?v=sNkB1DivMnk

It doesn't sound serious to me, especially the way it comes and goes. But I can't tell from the video where it's coming from.

We need more data to diagnose it, so some experimenting is needed - what happens when the engine is revved? Or the clutch is pulled in? Clutch in, but in gear? etc...

Does this only happen when cold?

It could still be the throw out bearing... does the clutch pull hard sometimes, or act not quite right? That plastic part has to slide in the bore, but if it's tight, can hang up.
Title: Re: metallic screaching sound on cold start -up
Post by: John M on December 11, 2011, 07:53:16 PM
I just did a search titled      youtube bmw motorcycleengine squeal  
that brought it up
Title: Re: metallic screaching sound on cold start -up
Post by: lodekka on December 12, 2011, 02:44:05 PM
Listening with a large screwdriver I believed the noise was coming from the clutch area. When the engine first starts then is no noise then within a minute it starts. Pulling the clutch in made no difference. Since the noise started I have not run it long enough to see if it disappears when the engine is warm.
It has been off the road for 12 months or more now as I believed it was a major strip down.
Title: Re: metallic screaching sound on cold start -up
Post by: Bob_Roller on December 12, 2011, 03:24:14 PM
If you have any problems removing the pushrod, there is a threaded hole in the end of the pushrod .

It's a small diameter fine thread, don't know if you can find a threaded fastener in the correct size to thread into it, then pull the pushrod/bearing out .
Title: Re: metallic screaching sound on cold start -up
Post by: jg928s4 on December 16, 2011, 05:52:20 PM
Mine does similar at odd times, I thought it was not going all the way into gear or clutch throw out not disengaging.  Because when I stomp on shifter, or pull clutch in and out it stops.  Only occurs when cold engine and it is cold out, guessing fluid not as viscous....
Title: Re: metallic screaching sound on cold start -up
Post by: wiemer on December 19, 2011, 04:01:05 PM
@ John:
Quote
cold weather (-2 celsius ) started bike got a sound I can best describe as being like a worn out water pump on a car. the sound came and went through 10 min of riding. Also I noticed some drag in the transmission when in neutral and releasing the clutch lever ( the bike edged forward slightly )
Still makes noise when  clutch released and in neutral?


....Maybe some dry sprockets in the tranny, on the shafts? That would explain  the bike creeping.
If one gear makes that bonding problem, one gear should be noiseless.

A dry, or dying bearing in the tranny, but that doesnt provoke the creeping.
You could lift up the bike, roll her over vertically up & vertically down, to grease dry tranny bearings...I know, hard to perform.
What is being done in cars is fill the tranny up way above max, drive a bit, and drain till normal level. might (sp)oil your clutch plate though....

I am curious, Wiemer.

Title: Re: metallic screaching sound on cold start -up
Post by: tvrla on December 20, 2011, 12:29:03 AM
By the way, it's normal for the rear wheel to creep with the bike on the center stand, engine running and in neutral. But if you hold the tire the movement will stop.
Title: Re: metallic screaching sound on cold start -up
Post by: fermin on December 20, 2011, 05:16:05 PM
mine creeps too, I think its normal
Title: Re: metallic screaching sound on cold start -up
Post by: John M on December 20, 2011, 07:02:49 PM
The creeping I referred to in my original post was with the bike off stand in neutral, when I released the clutch lever the bike tried to nudge forward this occurred several separate times . Very worrisome, I am going to drain the tranny tomorrow morning to inspect the gear oil for any telltale signs of a disintegating bearing before moving on to other suggested items (the oil was changed about 3,000 km ago in the summer and at that time the old oil I drained looked good and there was nothing other than a little grey paste on the magnetic plug.
Title: Re: metallic screaching sound on cold start -up
Post by: John M on December 21, 2011, 04:47:17 PM
Drained tranny this am  , old gear oil was pristine no metallic bits of any sort. so on to clutch throwout bearing and then re & re of starter motor
Title: Re: metallic screaching sound on cold start -up
Post by: tvrla on December 21, 2011, 06:43:55 PM
No metal bits in the trans oil is always good news! Now on to the cheaper problems.

That's a big relief!
Title: Re: metallic screaching sound on cold start -up
Post by: wiemer on December 29, 2011, 09:41:59 AM
Hi,

I posted the Youtube squeaking BMW on the German R45/R65 Forum (KleineBoxerForum), and somebody came up with this.
What is interesting he actually did not listen to the Youtube sound because of primitive computer (!), but he mentioned that on his bike, when the crankshaft rear main O-ring was going to die, he heard noises, like from a driving belt! After that, oil is coming out between the 'box and engine.
(he changed the O-ring 3-4 times. in 33 years)
(Others suggested rockers or valves, but that is not likely.)
Something to be ruled out, before opening up the gearbox!

Groetjes, Wiemer.

Hallo zusammen,

ich kann mir mit meinem langsamen Rechner zwar kein Youtube anhören. Aber wenn Ihr so etwas wie Keilriemen-Geräusch als Vergleich angebt: Wenn der hintere Kurbelwellen-Dichtring sich verabschiedet, kriegt er auch das Quietschen, weil die Dichtlippe zu breit wird und bei Mangelschmierung den sogenannten Slip-Stick-Effekt zeigt. Meine Kurbelwellen-Wedis (Wellendichtring DIN 3760) haben sich vor der deutlichen Leckage immer akustisch angekündigt. (Verbrauch drei oder vier Stück auf 150 Megametern in 33 Jahren)

Und weil ich das Quietschgeräsch nicht zuordnen konnte, habe ich auch schon mal den ganzen Zylinder abgezogen, um zu sehen, ob der Kolben vielleicht Freßspuren hat - hatte er nicht.

Guten Rutsch - aber nur in ein gesundes 2012 - nicht auf der Straße.

Brummbär/Michael
Brummbär
Brummbär
Dauerposter

 
Beiträge: 95
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Title: Re: metallic screaching sound on cold start -up
Post by: Air4Life on December 30, 2011, 10:37:05 AM
I think this was already mentioned; but just in case, it may assist in your diagnostics:  Does the sound change in relation to engine speed?  Do you believe it has a speed that matches the crank, or some other speed?
Title: Re: metallic screaching sound on cold start -up
Post by: John M on December 30, 2011, 02:54:00 PM
the noise goes up and down with engine speed
Title: Re: metallic screaching sound on cold start -up
Post by: Air4Life on February 29, 2012, 09:43:50 PM
Dubious information:

Well, if it goes up and down with the same apparent speed as the engine (1500 rpm - 5000 rpm) I'd say you can rule out the accessories section.  Your fuel pump, vacuum pump, your hydraulic pumps, your magnetos, and even your prop governor all should be turning  a lot slower than the engine speed.  So that part is good.  

If you mains were bad, the engine would have likely blown itself to bits by now.  So that's probably good too.  

Now my advice is not likely to be acknowledged by anyone here, but if you approach machines anyway like my friend does - just turn the radio up louder...

I can't even figure out why older posts keep showing up as new messages.
Title: Re: metallic screaching sound on cold start -up
Post by: nhmaf on February 29, 2012, 10:28:17 PM
I'm still betting on either throwout bearing/pushrod, or  possibly the diaphragm spring/clutch assembly is out of spec.   In any case - if it is liek that youtube sound, it certainly sounds like dry metallic rubbing, which is certainly not a good thing in most cases.

the pitch does change when you rev up the engine?
Have you pulled the drain plug on the transmission yet to look for metallic shavings?
Title: Re: metallic screaching sound on cold start -up
Post by: John M on March 07, 2012, 09:41:51 PM
I think the answer to my noise is the clutch throwout bearing,I have just pulled the transmission for an overhaul with circlip install and taller fifth gear and the clutch push-rod seemed to be bound to the front half of the throwout bearing so it was spinning in the bore. Thanks to every one for your diagnostics, you pointed me in the right direction.
     Best Regards  John    ( You nailed it Nhmaf )
Title: Re: metallic screaching sound on cold start -up
Post by: John M on March 07, 2012, 09:47:21 PM
I just went over the posts and want to include Monte and Wirespokes
in my thanks in addition to Nhmaf you all are batting 1000
                             Best Regards John
Title: Re: metallic screaching sound on cold start -up
Post by: tvrla on March 08, 2012, 10:39:50 PM
I don't quite follow you on what the problem was. The throw-out rod is attached to the center race of the bearing. The bearing should spin in the piston.

Are you saying the bearing is frozen and turns the piston when the rod is rotated?

IF that's the case, hopefully the bore in the transmission cover wasn't damaged.