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R100RS excessive noise emminating from rear drive train.

M

musclehealchance

New member
Seeking guidance please, noting that describing noises and asking for answers is a very opened ended pitfall. The bike is an '88 R100Rs with approx. 80Kmi. Its been parked in my garage since early summer as during the heated months of the year I do not use it much routinely but with early riding season here in Ky. coming up shortly I need to get something started on getting a better understanding of the noise coming out of the rear drivetrain and would be ready to take some action to remove things needing to be sent out for further inspection but what? Last ride on the bike I noted at speed a very audible but low whie coming from the bike, a sound that I can only describe a akin to the passing of an 18 wheeler, you know, that high pitched whine or whistle that they make from underneath when the tractor trailer is rolling along at highway speed. Fast forward to pulling the bike into my enclosed garage a near toe down speed I heard much noise as in meshing gears in a dry box(clackity clack), pulling in the clutch the noise lessened somewhat. I placed the bike up on the lift with rear wheel off the surface and rotated the wheel with tranny in neutral, definite noises from rotation, if I put it in gear(wheel off the surface) the meshing noise continues, once again if i pull in the clutch the noise lessens by fact of no-load on the wheel I conclude.
I have drained all fluids from the tranny on back to the FD and no telling particles were found in order to give me direction of the issue? I'm poised to pull the transmission, separate the FD from the driveshaft and send all 3 out for inspection at great cost simply for shipping and then some but that appears to be about all the options I have. If those of you that have something to comment on here would care to then please do and thanks! Bill Ed.
 
Pulling in the clutch doesn't separate the transmission from the final drive, it separates both of them from the engine. Is the noise still there if you put it in neutral? I have had it described as excessive, but my SOP with these bikes is to send the heads and transmission out for rebuild every 80K miles. By my timing you are there. Others push it out and often they get away with it. Shipping is not the great expense. I can ship a box to a qualified rebuilder in a 12x12x12 box for about $40. The rebuild though can cost $500. Final drives about the same and heads a bit less. The needed head work won't announce itself until the head of an exhaust valve pops off and grenades the piston and cylinder.

If you want to get to the minimum that you need to do, start with removing the final drive. That is the first step anyway if you are removing the transmission. If you are going to eventually remove the swingarm it is easier to remove the driveshaft bolts inside the rubber boot as the first step while you can lock it in position with the wheel and the transmission. The final drives on these bikes don't give much trouble and it is unlikely to be the problem. Though I rebuild heads and trannies at 80K, I run the FD's until they show problems. Most likely what you have is a destroyed front universal on the driveshaft. Remove the swingarm pivot pins and withdraw the swingarm. You can pull the universal far enough out the front to inspect it.
 
Re: Excessive noise R100RS

Thankyou Lee for the response. I tend to agree with you that intuitively the source of the noise could be at the U- Joint. More to follow maybe once I separate the components.
 
STEVENRANKIN said:
At 80K, I had to have the rear wheel/differential splines replaced on my bike. St.
Click to expand...

The 88 is a monoshock which does not have splines in the rear wheel / final drive. By the way a "differential is for a two wheel drive. With one wheel there is nothing to differentiate. It is just a final drive (which looks suspiciously LIKE a differential).
 
noise

musclehealchance said:
Seeking guidance please, noting that describing noises and asking for answers is a very opened ended pitfall. The bike is an '88 R100Rs with approx. 80Kmi. Its been parked in my garage since early summer as during the heated months of the year I do not use it much routinely but with early riding season here in Ky. coming up shortly I need to get something started on getting a better understanding of the noise coming out of the rear drivetrain and would be ready to take some action to remove things needing to be sent out for further inspection but what? Last ride on the bike I noted at speed a very audible but low whie coming from the bike, a sound that I can only describe a akin to the passing of an 18 wheeler, you know, that high pitched whine or whistle that they make from underneath when the tractor trailer is rolling along at highway speed. Fast forward to pulling the bike into my enclosed garage a near toe down speed I heard much noise as in meshing gears in a dry box(clackity clack), pulling in the clutch the noise lessened somewhat. I placed the bike up on the lift with rear wheel off the surface and rotated the wheel with tranny in neutral, definite noises from rotation, if I put it in gear(wheel off the surface) the meshing noise continues, once again if i pull in the clutch the noise lessens by fact of no-load on the wheel I conclude.
I have drained all fluids from the tranny on back to the FD and no telling particles were found in order to give me direction of the issue? I'm poised to pull the transmission, separate the FD from the driveshaft and send all 3 out for inspection at great cost simply for shipping and then some but that appears to be about all the options I have. If those of you that have something to comment on here would care to then please do and thanks! Bill Ed.
Click to expand...

The noise might be coming from a failed output shaft bearing in the transmission.

My '93 R100RT had this occur at 20k miles on a Nova Scotia trip, years ago. The symptoms were similar to what you describe, but not exactly.

My bike, on the centerstand, rotate rear wheel in neutral, noise was heard.

The bike made the 2500 mile trip as there were no dealers there to diagnose so I just rode home at a slower pace.

Upon returning, I opened the tranny to find the front bearing on the output shaft (closest to the engine) was sloppy. You'll note that there is a tray in that upper right corner of the tranny that takes splashed oil and directs it to the bearing. I had a buddy go through it and he advised a new bearing with an extra ball, increasing the surface area to the race. I believe the stock BMW bearing had 12 balls and the new one had 13, but I could be wrong.

If you don't find another cause, disconnect the driveshaft and rotate just the output shaft to see if it's making noise and you'll know if it's in the tranny or not.


Hope it helps,

I rode it another 40k with zero issues.
 
Oh well

beemerphile said:
The 88 is a monoshock which does not have splines in the rear wheel / final drive. By the way a "differential is for a two wheel drive. With one wheel there is nothing to differentiate. It is just a final drive (which looks suspiciously LIKE a differential).
Click to expand...

Excuse me for posting.
 
Differential

beemerphile said:
The 88 is a monoshock which does not have splines in the rear wheel / final drive. By the way a "differential is for a two wheel drive. With one wheel there is nothing to differentiate. It is just a final drive (which looks suspiciously LIKE a differential).
Click to expand...

Although technically correct, many of us kids were shown the "ring/pinon" section of the rear end of the family car and were told by the 'ol man, "boyyyy....that there's where the diff-a-wrench-el sits".

Of course, as we got older, many of us look at any ring/pinion gear housing and still think of it as a differential.....:)
 
beemerus said:
I believe that beemerphile was just trying to be deferential....
Click to expand...

Well, I thought I was just injecting a bit of fact, but at this point I apologize for pointing it out. I thought one of the reasons we hang out here was to learn things. I certainly have on many occasions when I found out something I thought was true was not. I get embarrassed when I get called on it, and I always think maybe I oughta be more sure before I say something. A closed mouth gathers no feet. But since we seem to live a world where if something is wrong long enough it qualifies as right, or where a person who points out an error is only intending an insult, well, I just need to apologize and shut up. I don't claim to know it all and I intended no insult.
 
Lee -

I think things should be OK. You confirmed something that I had in the back of my mind. When the discussion first came up, I immediately looked to see what kind of drivetrain was on this bike. I saw it was a monolever. The other drivetrain of the era was the paralever. I can never remember when the idea of the rear wheels just bolted in from the left side...no swingarm, nothing block it. I sort of thought that one of those models didn't have drive splines since it just bolted to the "differential".
 
RPGR90s said:
Although technically correct, many of us kids were shown the "ring/pinon" section of the rear end of the family car and were told by the 'ol man, "boyyyy....that there's where the diff-a-wrench-el sits".

Of course, as we got older, many of us look at any ring/pinion gear housing and still think of it as a differential.....:)
Click to expand...

Can you still call it a pumpkin
 
Re: R100RS Excessive Drivetwain Noise.

Thanks for the entertainment guys, I don't believe there is actually any unnecessary roughness occurring, just an insufficient use of emoji's! Anyways, the weekend forecast here is for rain/wind and a likely prospect for greasy hands! Bill Ed
 
Just my experience.. I had a whining noise from my rear drive. Drove me nuts. I changed the oil twice and the third time added some of the Moly lube and now all is quiet.
 
I am not upset

I am Not upset, just a little embarrassed.

Written text has less capacity for emotion as does voice or face to face communication. I am not an emoji user. Maybe next time. LOL
 
Last edited:
A fine whine

Back to the issue. Based on mileage I'm inclined to open the transmission and look at the output shaft forward bearing. Symptoms sound similar to that bearing going out and more likely than a rear drive failure.
 
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