K75S Clutch Spline Lube Reveals Oil in Intermediate Housing

[detbmw]

This afternoon my buddy Jeff & I pulled the transmission off of my '88 K75S. We immediately noticed oil around the walls of the intermediate housing. Not on the clutch, and not on the transmission. It seems to be engine oil coming from maybe the Rear Main Seal? Oil was not pouring out, it was just coating the walls and the bottom.





We have a couple questions:
1) Is this if immediate concern? Can the bike be ridden for another 25K before replacing the rear main seal (if that is the problem), or should this absolutely be fixed before the bike is ridden another mile?

2) Can the rear main seal be replaced from outside the engine if we pull the clutch off?

Also, we happened to remove the clutch release arm and about 1/2 oz of oil spilled out of the boot. Should we be concerned about that?

[frankenduck]

if its spun off like that then I'd guess its the clutch nut O-ring that is the villian, not the rear main seal..  You should replace it while you have things opened up.

Gear oil coming out of the boot is normal when the clutch arm is released..

[Rick G]

Not saying the O ring isn't leaking but if it is then the oil would be on the clutch. I would say that it is more likely to be the rear main seal but if the seal is leaking and not the O ring it would be unusual.
If you have it down that far you should replace the seal regardless as it is probably 25 years old and can be done from the outside after the clutch carrier comes off.
Have a look through the Lieberry, Frankenduck has a terrific collection of his own and others experiences in dong all sorts of jobs and there is one there for the clutch and seal for sure.

[frankenduck]

If the O-ring is leaking then it can take a while for the oil to make it to the friction surface.

Several years ago I purchased a K100RS4V in LA that had a leaky O-ring. (The PO pointed the drip out before I purchased it as he knows K bikes and is an honest guy.)  I put about 1,500 miles on it before getting it home to take it apart and the clutch friction surface was still dry when I pulled it apart.  What happens is that the oil spins out of the clutch basket before it gets to the friction surface.

[detbmw]

Thanks, I'll be ordering an o ring and a seal tomorrow.

[frankenduck]

Thanks, I'll be ordering an o ring and a seal tomorrow.

Why replace the main seal if its not leaking?

Take the clutch apart before ordering anything.  If the oil is leaking inside of the clutch basket then the O-ring is leaking.  It its in front of the clutch basket then it is the main seal leaking.

[detbmw]

Thanks, I'll be ordering an o ring and a seal tomorrow.

Why replace the main seal if its not leaking?

Take the clutch apart before ordering anything.  If the oil is leaking inside of the clutch basket then the O-ring is leaking.  It its in front of the clutch basket then it is the main seal leaking.

I ordered from Bob's BMW this morning, but the parts will not ship until Monday. Jeff & I plan to take the clutch apart this afternoon. If I don't need the main seal, I can call and cancel that part.

Thanks for your quick responses, I really appreciate the help.

Rich

[frankenduck]

In the Lieberry: K bike clutches

[detbmw]

In the Lieberry: K bike clutches

Thanks, I had already printed it.

Once we removed the clutch nut, oil began seeping out. It was just the o ring, so I called Bob's and cancelled the real main seal.

The clutch plate is in good condition.

Hopefully I'll have my parts on Tuesday and I'll be back on the road (on that bike  ) no later than Wednesday night.

Rich

[detbmw]

My buddy Jeff crafted a tranny trolley (patent pending) to move the whole transmission (and attached parts) around on the lift (that's Jeff in the background).





Bike with the back-end gone:



Rich

[detbmw]

I think we are about half-way to getting the bike back together. It was slow work tonight, only because we have never done this before.

The o-ring is in place on the engine output shaft and the lock nut is torqued down. Clutch is back together, transmission is on the bike (clutch splines are lubed, first time in 25 years), and the starter is on.

Tomorrow afternoon we have put on the: battery, tray above the battery, computer do-hickey into the side of the tray, rear fender, left foot peg mount, muffler, side case brackets, rear brake caliper, speedometer cable, rear brake disc, rear wheel, and bottom nut on the rear shock. We left the final drive on the swing arm, we just remounted it and lubed it two weeks ago.

There is a little rubber bit that goes on the a-type frame on the bottom side of the muffler that the center stand smacks into when you raise it. It was missing when I bought the bike, so I ordered one and it is now on the muffler. We also took apart the side/center stand and lubed it. Now they both move like a hot knife through soft butter.

I hope to be riding the bike tomorrow night.  :yippee:

Rich

[detbmw]

We finally finished the brick Friday night. The shift is as smooth as a hot knife through soft butter. What an incredible difference a little lube and several hours work make.

Now on to the next problem...

[TimTyler]

Why replace the main seal if its not leaking?

Because those seals don't last forever and the replacement part and procedure is cheap and easy once you're into the clutch?

[BobZ(IL)]

Why replace the main seal if its not leaking?

Because those seals don't last forever and the replacement part and procedure is cheap and easy once you're into the clutch?

You might be surprised at how long they last.

[TimTyler]

I might be.

How long do they last?

[frankenduck]

As long as fork seals - until you start worrying about it...

[BobZ(IL)]

I might be.

How long do they last?

Generally measured in 6 figures, not five

.

As long as fork seals - until you start worrying about it...

 That...and once someone starts replacing them, it seems to go on forever.

[detbmw]

Three is one problem related to the clutch spline lube that we did.

When we were reassembling the bike, I came up one screw short of a full bike. It took me until now to find the correct nomenclature in a manual to describe it.

The fuel injection control unit sits under the seat. On the left side of it is the control unit connector plug. You have to push a flat-bladed screwdriver in to push down on the retaining tab in order to get it to pull out. Well, this connector plug has a very small screw near the front of it. For some insane reason I removed the screw, maybe thinking that it would aid in getting the connector plug out. While reassembling the bike, I could not find the screw. As we disassembled the bike, I had put sets of nuts, bolts, washers, screws, etc., into ziplock baggies and wrote on the bag which part of the bike they went to (left foot peg mount, transmission to engine housing, etc.). Somehow I managed to lose this one screw.

I have found the control unit on fiche, but not the connector plug.

I don't know the purpose of the screw. The bike runs without it.

If you have the K100 & 75 2-valve Haynes manual, it is on page 145, picture 17.13.

I feel so screwed (pardon the pun).

Rich

[frankenduck]

Three is one problem related to the clutch spline lube that we did.

When we were reassembling the bike, I came up one screw short of a full bike. It took me until now to find the correct nomenclature in a manual to describe it.

The fuel injection control unit sits under the seat. On the left side of it is the control unit connector plug. You have to push a flat-bladed screwdriver in to push down on the retaining tab in order to get it to pull out. Well, this connector plug has a very small screw near the front of it. For some insane reason I removed the screw, maybe thinking that it would aid in getting the connector plug out. While reassembling the bike, I could not find the screw. As we disassembled the bike, I had put sets of nuts, bolts, washers, screws, etc., into ziplock baggies and wrote on the bag which part of the bike they went to (left foot peg mount, transmission to engine housing, etc.). Somehow I managed to lose this one screw.

I have found the control unit on fiche, but not the connector plug.

I don't know the purpose of the screw. The bike runs without it.

If you have the K100 & 75 2-valve Haynes manual, it is on page 145, picture 17.13.

I feel so screwed (pardon the pun).

Rich

The connector is part of the wiring harness and not a separate part.

That screw helps hold the connector housing onto the connector.

You probably don't even need it but if you PM me your mailing address I'll mail you one.

[detbmw]

The connector is part of the wiring harness and not a separate part.

That screw helps hold the connector housing onto the connector.

You probably don't even need it but if you PM me your mailing address I'll mail you one.

I received the screw in the mail today! It had kinda pushed a hole in the envelope, but the tape kept it from going anywhere.

I don't know when I will get from East Texas to the West Coast, but I will definitely buy you a beer.

Rich