Okay guys.....here's my predicament. After my 30+ mile round trip commute and letting the bike sit I get maybe a drop of oil around the weep hole but even if the bike sits overnight I get no dops on the ground. This means every 500 miles or so I add a little bit of oil to keep it where it's supposed to be. My question is should I even mess with this? From my background in mechanical issues I'd think this could be a "fix it until its broken" case. Opinions?

I am presuming you mean the seal breather hole just behind the water/oil pump. If so I would not touch unless something else is also required to be done then put a kit through it or untill its leaving a quantity of oil behind each time you stop that you aren't comfortable with.

Sorry should have been a little more clear! I meant the drain hole that is usually a sign of a rear main seal leak. It's def engine oil, but the leak has shown no sign of getting worse so I'm thinking to just keep an eye on it.

So it's at the bottom of the clutch housing behind the engine?
If so, eventually as it gets worse, the clutch may start to slip. What is often diagnosed as a rear main seal leak, is usually an O-ring that has become hard with age (behind the nut & washer that holds the clutch housing basket to the engine output shaft. A leak there goes directly onto the clutch disc as opposed to running down the housing forward of the clutch basket
Let's assume for a moment that your clutch lining material is not excessively worn (might be a big assumption), You can save it by pulling the trans out sooner for a spline lube. While you're in there, remove the clutch assy and replace both the o-ring and the rear seal. There is newer info on installation of the seal, it is recommended that you leave it just slightly outside of (proud) of the engine case rather than pushing it into the back of the engine till all the way flush.

Mine does the same. I have taken the oil pan off and resealed as it looked as if it could have been coming from there. Next I have added a tin of Wynn's Engine Stop Leak. I am as skeptical about this and other magic cures as anyone but have read positive reports from the K1100 forum that it seems to work - and if the chemicals in it return flexibility to old, hard rubber that would seem to make sense. Of course if it does work there's no telling for how long. We shall see - all part of the fun eh?

Cheers
Dave

ibjman wrote:
What is often diagnosed as a rear main seal leak, is usually an O-ring that has become hard with age (behind the nut & washer that holds the clutch housing basket to the engine output shaft.

I'll second that. In fact, I've only ever changed an output/balancer shaft seal once and that was because I'd bought one thinking that it would be the culprit only to find that it was okay (as I was in there and had a new seal I swapped it anyway).

The O-ring change is bit of a pain. The six clutch retaining screws and washers should be replaced along with the centre retaining nut and collar. The pain is getting the old O-ring out.

The clutch carrier will not come off the output/balancer shaft splines while the O-ring is in place and the O-ring is down the shaft inside the carrier.

The clutch carrier will slide on the splines a few millimetres, I pull it forward to get the O-ring near the threads:



Then hook it out:



The clutch carrier will slide off now to inspect the seal.

When re-assembling, I use the old collar and retaining nut to seat the O-ring before using the new parts and torquing it up.

Thanks for the pictures that really paints a clear picture of what I'm getting myself into. Will definitely be prepared to do more than just change the o-ring while I have the bike apart. The temptation is to put some more miles on it before getting to work but I'd hate to ruin a good clutch...

To get the old O ring out I use a cheap small screwdriver and make a chisle point then cut through the O ring in 4 places and dig each bit out seperately. You wont get the clutch basket off without removing the O ring.

Think I know what popular opinion will be here, but since the leak is so slight I was considering attempting the leak stop repair. I'd like to avoid gumming other components up with this, but since I have such a small leak and I am thinking it may just be a dried up o-ring would it be reasonable to try this as a remedy to get a riding season out of the bike before tearing it down in the winter?

My K100 used to mark its territory by a little drip for 2 years before I fixed it so unless the spot on the floor is bigger than say 20mm diameter over night I would not be overly concerned.

After removing the oil pan and resealing my oil leak has now stopped. Worth ruling this out before major surgery perhaps?

I did add the chemical concoction above at the same time but have ony run the bike a few miles since and opinion is it takes some time to make a difference to old and hardened oil seals.

Cheers
Dave

A little update on my "minor" oil leak. 

I decided to change my transmission oil since it was measuring low (126mm below the fill hole).  The old oil did not look great, but I just had a normal amount of metal on the magnet so I thoroughly cleaned that off and flushed the transmission with new oil.  I serviced the bike to the 116mm mark and took it around the block a few times.  Smoothest shifts I've had on this bike since my ownership so I felt great.

I came out to the bike a couple of hours later and now have a small puddle (4-5" in diameter) under the bike.  The leak is coming from the clutch bell housing.  The bike wasn't leaking a terrible amount of oil with the low oil level, but I presume that servicing it to the proper level gave me a proper indication of what the leak is an where it is coming from.

My guess would be input shaft seal at the front or the clutch pushrod seal.  Either way, I guess it's time to get dirty and pull the transmission.  While I'm in there I will be looking for that small engine oil leak that is nagging me as well!

Hi, here is my experience with clutch and transmission. Ten months ago I changed friction plate, O ring on engine side and seal on transmission side. I was afraid to open story with main seal behind the clutch housing. It took me six hours with friendly assistance. I did it by the book, marked clutch elements position, tight every bolt by proper force. Parts prepared: new clutch bolts and main nut, O ring, friction plate, transm. seal  (cca 80 euros)
It was enough obviosly: no leaks from bell housing, clutch works properly.

Best regards

Any oil in that bell-housing area is bad news. The oil seals on the crankshaft tail and the gearbox nose aren't there for decoration.

If you need to know how I know this, read my intro post...

You can get to that seal without removing the gearbox but if as much oil as that has escaped then it will be all through the clutch and it will need attention (don't ask). It is a good opportunity to replace the rear main seal and O ring too.

Still working on how to post pictures here so I hope this works.  What I found when I decided that it was time to dig into my bike and really get to know it.  The good news is that all of the splines looked great and were properly lubricated.  Clutch is stamped from '95 and looks a little wet so I am replacing that while I have the bike apart.  As was suggested by multiple forum members here is a picture of my leak and not so clean clutch bell housing.



(The picture came out rotated 90 degrees so obviously as gravity would confirm the oil flowing out to the bottom)

Okay K gurus.....while I am in here what else should I replace?  My transmission is leaking on the front end shaft seal so that's going to be replaced, but I want to make sure that I maximize the use of my time that I spent disassembling the bike.

Oh, a handy tool to remove the transmission....guide pins.....but I just bought 2 4" 8mm bolts with plenty of shank and cut the bolt heads off.  Price to me was $0.78 US and they worked perfectly!  I need a clutch alignment tool so any tips for that would be great!  Looking forward to the responses!

Both Motorworks and Moto Bins will happily sell you a clutch alignment tool. Very likely your nearest BMW dealer too. Worth their weight in gold! Which isn't a lot, the one I have is made of aluminium ;-)

Really, it's not rocket science to get the new disc re centered without buying the tool. a long slender object with a larger round bushing around it can be improvised.
find something like a long 1/4" drive extension.......build up an area the right distance from the nose with a roll of electrical tape, until the spool is big enough to fit the Inside diameter of the clutch disc splines. Or slide some kind of a thread spool around a pencil, them turn it down as needed to fit the clutch disc. You just want the clutch disc centered enough so you can get the trans back in through the middle with the bolts lined up on you aligning studs,

So the centering tool is only used to help with alignment for the purpose of the transmission spline? Seems like I should be able to get by without the centering tool if that is the case!

I have done the job without the tool but if you can get one then by all means get it becaise it does make the job easier.
I presume you are going to replace the large seal behind the clutch carrier and the O ring behind the nut in the centre.
When you try to get the O ring out get a small flat blade screwdriver and sharpen the end to a chisel blade then cut through the O ring in 4 places and pick it out easily. It saves your hair and the kids don't learn new words.

Rick are you referring to the rear main seal? I was thinking about leaving it be, but I'm right on the fence about it. The bike is a 93 so things are getting older I would hate to repair the current problems just to experience another shortly after. I'm also concerned about creating additional problems. Once I get the flywheel off I'd I will have a better idea of the condition of the rear main.

Had to stop for the night because I can't go to work tomorrow with oil stains all over my hands!

Sure am talking about that. We might have been at our peak at 20 years but a seal has a life expectancy of 10 years so it is well past its use by date. I always replace them unless it is obvious that it has been done recently because the work to be done when it does fail from being disturbed is not worth the $30 to replace it now.
I use OEM for them as the directional seals in VITON are not available here in the correct width.
You do need to use VITON as the Nitrile seals don't stand up to the heat.

Although 90 percent of the time, the bulk of the leakage is caused by the O-ring, I chose to replace mine as rick indicated.....I think it's reasonably cheap insurance given the amount of work to go back in later. Others may recommend just the oring, but I think that is not the best logic.
Also, re sure to read the posts about installing the new seal correctly.......it may have to be left just a hair up above the back of the crankcase flange surface. and there are proper procedures for pre treating the sealing surface of the seal itself depending on what style it is.
Regards, ibj...