R1100GS oil leaking onto the Exhaust

[Buffalo Chirp]

My 99 R1100GS has an oil drip coming off the catalytic converter as it sits on the center stand.  I've been smelling it for a while.  And I see residual oil around the mounting points of the foot peg brackets and the Swing arm pivots.  Hmm.  Any suggestions?  It continues to leak as it sits undisturbed.  I've topped up the gearbox oil and  it feels like that heavier grade oil.  When removed the rear shock and I lift the Driveshaft/final drive, I can see oil up in there in that box below the Clutch Throw-out bearing.   Where could this be coming from?

[Doctare]

I would check my transmission oil level first.  I'd also check my hydraulic (brake)  lines.

[AndyS]

Where there is oil on the colder parts (not the cat') smell it, you should identify by smell whether that is Engine of gearbox oil.

As to where it is coming from...first of all establish which oil it is and then we can start making more suggestions.

[Jim Moore]

There are two seals at the back of the transmission, input and output shafts.  My bet is it's one of those. Hopefully it's the output shaft seal. It can be replaced from the outside of the transmission (and maybe in situ). The input shaft seal has to be replaced from the inside. Thanks BMW!

 

Whichever it is I'd fix it sooner rather than alter. A bad input shaft seal will all ow oil to migrate up the clutch pushrod and ruin your clutch. Is your clutch slipping at high rpm in 4th and 5th gear?

[dirtrider]

6 hours ago, Buffalo Chirp said:

My 99 R1100GS has an oil drip coming off the catalytic converter as it sits on the center stand.  I've been smelling it for a while.  And I see residual oil around the mounting points of the foot peg brackets and the Swing arm pivots.  Hmm.  Any suggestions?  It continues to leak as it sits undisturbed.  I've topped up the gearbox oil and  it feels like that heavier grade oil.  When removed the rear shock and I lift the Driveshaft/final drive, I can see oil up in there in that box below the Clutch Throw-out bearing.   Where could this be coming from?

 

Morning   Buffalo Chirp

 

Something is leaking back there, could be the transmission output shaft seal leaking, or the rear seal on the input shaft leaking (one under the slave cylinder) IF the slave cyl gasket is missing, cut, or a drain hole drilled, or possibly the neutral switch/gear position switch seal leaking, or even the final drive pinion seal leaking  with the gear oil then running forward through the swing arm. Or even something else leaking & somehow running down into that area.

 

You should clean that area up best possible  then take a short ride to see if you can identify WHAT the heck is actually leaking. Maybe even loosen the clamps on the final drive boot & see if there is a lot of gear oil back there in the rear boot. 

 

If you just can't find the leak then there is an oil additive (available at most better auto parts stores)   that you add into the oil, or into the transmission gear oil, etc, then ride it a short ways, then you use a "black light" to see where that additive (oil trace)  is coming from. 

 

When I'm looking for a leak in that area I usually clean that area with a 1 gallon garden sprayer filled with common mineral spirits. Usually takes a few cleanings to get it clean enough to see anything. 

 

If it's real bad & caked on heavily I will sometimes spray on a few applications of  WD-40, then let it sit overnight, (or even a day or two). THEN use the garden sprayer & mineral spirits for the final cleaning.  

 

You need to clean it first,  then look for signs of drooling at all the possible leak points after riding. 

 

 

[taylor1]

If you can get some S101, it really cuts oil and grease in a very quick fashion

[Buffalo Chirp]

I'm on it.  I am really grateful for all the advice.  I'll check the brake fluid but it sure feels and smells like Transmission oil.  I topped that off after smelling the burn on almost any ride, no matter how short.  Then she just started pissing; incontinence.  1999 was a long time ago.  What about a pressure wash (gently).  I've got a chemical resistant spray bottle with turps.  That's probably best.  I changed the throw-out bearing years ago, 2008?  could oil be coming out of that seal?

Mr. Moore, I have noticed no slippage on the clutch.  I've got about 150000 miles on it.

thanks again.  My riding buddies are giving me shit about the 1100.  Time to retire it and part it out.  But, It's a great bike and I've now decided to address the ABS issue, having learned on this forum that it isn't as bad as the 1150.  I'm inspired.

I'll keep you posted.

[Jim Moore]

If you already know how to pull the swingarm you might as well get to work. I'm betting it's the output seal since your clutch isn't slipping.

[dirtrider]

17 hours ago, Buffalo Chirp said:

I'm on it.  I am really grateful for all the advice.  I'll check the brake fluid but it sure feels and smells like Transmission oil.  I topped that off after smelling the burn on almost any ride, no matter how short.  Then she just started pissing; incontinence.  1999 was a long time ago.  What about a pressure wash (gently).  I've got a chemical resistant spray bottle with turps.  That's probably best.  I changed the throw-out bearing years ago, 2008?  could oil be coming out of that seal?

Mr. Moore, I have noticed no slippage on the clutch.  I've got about 150000 miles on it.

thanks again.  My riding buddies are giving me shit about the 1100.  Time to retire it and part it out.  But, It's a great bike and I've now decided to address the ABS issue, having learned on this forum that it isn't as bad as the 1150.  I'm inspired.

I'll keep you posted.

Morning   Buffalo Chirp

 

No power wash as that can cause other problems if it blasts it's way into the rear mounted switches. Turpentine probably won't do much on oil removal. Common mineral spirits is much better.  

 

Check the final drive boot for gear oil before tearing the front apart. Not conclusive but a possibility. Gear oil can run from rear to front or front to rear inside the swing arm so keep that in mind. 

 

When you (changed)  installed the slave cylinder bearing years ago did you modify  (cut a slot) in the slave gasket or drill the transmission case to add a slave cylinder drain hole????????????

If so then you could have a leaking rear input shaft seal dripping oil out of that added drain.  

 

If you do find that the rear output shaft seal is leaking check the output shaft for lateral & fore/aft movement as you could have internal bearing problems. 

 

 

 

 

Edited January 16, 2021 by dirtrider
Edit to reflect correct model info

[Jim Moore]

DR, you mentioned "slave cylinder." I think he's on an R1100GS.

[dirtrider]

2 hours ago, Jim Moore said:

DR, you mentioned "slave cylinder." I think he's on an R1100GS.

Afternoon Jim

 

Good catch, for some reason I was thinking 1150, I need to scroll to the top on these longer threads.  

[Buffalo Chirp]

Would you all be surprised to find out it was the Gear Indicator/Idle switch, probably the o ring and the oil seal.  Dirtrider, you nailed it.   I think this is the most disappointing, maybe the only disappointing engineering on this bike.  Otherwise, I think it is very intelligently designed.  But to stash that switch, which penetrates the transmission housing below the oil level, with both an o-ring and an oil seal (the switch actuator is a rod coming out of the gearbox), and which requires the removal of the swinging arm to replace?  That was an oversight, to say the least.  yeah, I was very happy to see a very clean drive shaft with perfect splines and the final drive feels wonderful.  Bob's BMW had the parts.  Would anyone recommend any other replacements while I'm in here.  The swinging arm boot?  It looks fine; supple and unblemished.  Do the O-rings on the ABS sensor in the final drive often leak?

Thank you all for your input.

[Michaelr11]

On 3/18/2021 at 11:32 PM, Buffalo Chirp said:

Do the O-rings on the ABS sensor in the final drive often leak?

 

There are two O-rings in the final drive where the ABS speed sensor goes through.  They are inexpensive and I would replace them if you are working there.  If the one on the inner side of the FD is seeping, it will make an accumulation of grime mixed with brake dust, and it will all be hidden beneath the caliper and rotor.

 

[Buffalo Chirp]

Excellent suggestion.  There was plenty of grime.  I'm slowly putting it back together.  It's a project, for sure but it's so fun to ride.

Thank you for your help.

[Buffalo Chirp]

I am continuing to re-assemble my R1100GS.  The oil seals at the rear ABS sensor were indeed cracked and leaking.  Replaced them, thought I was ready to install everything.  Forward universal joint flops back and forth easily in one direction but hardly moves side to side in the other direction.  Would this indicate what I think it indicates.  Impending failure?  Did i just luck out finding a bad u-joint or do the forward u-joints always have VERY limited movement in one direction? 

I kind-a thought so.  I'm looking at having a proper repair shop install a new u-joint, aren't I?

Thanks again for your help. 

If anyone knows where I could get the ABS pump rebuilt, I'd be interested to hear about it.  If you'll recall, it's a 1999 1100GS with 2nd generation system.

[strataj]

7 hours ago, Buffalo Chirp said:

I am continuing to re-assemble my R1100GS.  The oil seals at the rear ABS sensor were indeed cracked and leaking.  Replaced them, thought I was ready to install everything.  Forward universal joint flops back and forth easily in one direction but hardly moves side to side in the other direction.  Would this indicate what I think it indicates.  Impending failure?  Did i just luck out finding a bad u-joint or do the forward u-joints always have VERY limited movement in one direction? 

I kind-a thought so.  I'm looking at having a proper repair shop install a new u-joint, aren't I?

Thanks again for your help. 

If anyone knows where I could get the ABS pump rebuilt, I'd be interested to hear about it.  If you'll recall, it's a 1999 1100GS with 2nd generation system.

https://modulemaster.com/collections/abs-control-module-rebuilds 

[Buffalo Chirp]

Thank you Strataj. They want $350 to rebuild that module and that's great news.  I'll just need to remove it and ship it to them.  As for the u-joint, Phoenix Rack and Axle installed the new u-joint with an exact replacement, eg, not serviceable.  Cost; $100  Turn around time: 45 min.  They happily ship.

Once again, I am very grateful to all who contributed to my ride to school today.  The bike is just so smooth, and I notice the absence of a certain shake that prop shaft must have been making. 

[Gary E Reynolds]

I’ve got the same problem. I’ve been told that using BMW Synthetic Oil can cause this. I have a blown gasket on left cylinder 🤦🏼‍♂️. I can only imagine how much this is going to cost me. But I love my GS 2010 model.