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Where is this oil coming from? '85 K100RT

oldnslow

It's a way of life!
Working on my 85 K100 RT. A recent under body (of the bike) inspection revealed a coating of that black oily paste that is common with a slow, very slow seepage type of leak. It is on the underside of the swing arm, above the clutch actuator. It is not leaking, showing around the seam between the engine and trans. It doesn't drip, just a fuzzy coat of diry black oil. it is very isolated to just above the clutch actuator. I'll try to post a picture.
 

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A couple of possibilities come to mind. Look at the canter bottom of the bellhousing for a round hole - less tha 1/4" in size. See if it is tracking back from that hole. This is just a drain from the dry bellhousing cavity but rear engine seal leakage or transmission input shaft seepage will wind up here at the bottom of the bellhousing.

The other possibility is it is coming from the clutch pushrod boot.
 
Push rod boot is new, and the bell housing doesn't have any leakage/seapage coming from the drain hole. The engine seal is new. Is there any thing that could be leaking from the swing arm pivot points? Or from the swing arm boot?
 
Push rod boot is new, and the bell housing doesn't have any leakage/seapage coming from the drain hole. The engine seal is new. Is there any thing that could be leaking from the swing arm pivot points? Or from the swing arm boot?

Nothing from the swingarm pivots. The transmission output shaft seal could seep into the swingarm and then seep a little past the boot.
 
Sholud I be concerned? The amount in the picture is how much seeped out in the last 8000 miles. (since my last spline lube and seal change)
 
Maybe it is just me, but if what is shown in your photo is what has resulted in the last 8000 miles, I would wipe it down with a nice cleaner and look at it after a few miles, then go longer between inspections, then even longer. Then make your decision based on what you see accumulating and from where....:dunno
 
That amount? I'd check the transmission oil level and then forgeddaboutit..

If the oil is too high it may mist up a bit on the rear.. the transmission vent is cleverly located under the battery tray.. you might try taking a look and see if it's been venting.

BTW - please read: http://forums.bmwmoa.org/showthread.php?t=46057 - I've added that info to the thread title..
 
I definitely have oil seeping from the small hole in the bell housing. Drips on the belly pan, then on the garage floor. Cleaned it all off with brake cleaner, but as soon as it's ridden longer than an hour, I can see the oil again. It smells like motor oil, so I'm assuming it's a rear engine seal??? What's the prognosis?? I'm not that well equipped to pull this apart in my garage.
 
I definitely have oil seeping from the small hole in the bell housing. Drips on the belly pan, then on the garage floor. Cleaned it all off with brake cleaner, but as soon as it's ridden longer than an hour, I can see the oil again. It smells like motor oil, so I'm assuming it's a rear engine seal??? What's the prognosis?? I'm not that well equipped to pull this apart in my garage.

Could be the engine rear seal, but more than likely it is the O-ring on the nut that holds the flywheel to the back of the crankshaft has gotten brittle and is seeping.

This requires removal of the trans and the clutch. How soon (if ever) you address this depends on how much is leaking and if you notice any slippage to the clutch.

Also try not filling the engine oil above the dot. One of my bikes leaks when ridden hard if the level is above the dot but not when it is at the dot.

Any slippage or persistent heavy leakage, count on doing a clutch job soon.




:dance:dance:dance
 
I just had both those seals replaced. Not haven't taken the transmission out before, I decide to have someone else do it. I could have done if it was cooler but I am in Georgia and it was hot.

I had let it leak for some time before deciding to have it fixed. Financial constraints put it off. It can be a pricey repair, most of the bill being labor. Have them check the play in the shifter while they are in there.
 
Thanks everyone, I bought this bike over Labor Day weekend and the PO had just changed the oil. The entire window is just about filled, maybe there's a fraction of a millimeter of clear showing. It leaked more when I first got it then now. Is it an overfill issue?? Clutch doesn't slip, just needs an extra tug on the shifter, (sometimes), going from 4th to 5th. Other than that, it runs good.:thumb
 
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