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TECHNICAL MOTOBRICK WRENCHING In Remembrance of Inge K. => The Motobrick Workshop => Topic started by: Smudgemo on August 04, 2025, 10:41:14 AM

Title: K75 Oil Leak and Clock Issue
Post by: Smudgemo on August 04, 2025, 10:41:14 AM
I have a '92 K75 RT that has been sitting for nearly 20 years back on the road and working well, but a few things still to work on.  One is the clock.  It was very faint so I followed the instructions to clean the connectors as outlined in an article on The Internet BMW Riders site, and it's pretty good but doesn't display a few numbers well.  I'm wondering whether it's worth going back in and working the connectors again.
(http://[attachment id=1 msg=142769][/attachment])

The other issue is oil leaking from the filter cover plate.  Couple of drips each night in spite of a new o-ring (and I'm starting to think I know why the prior owner broke one of the three bolts which took this bike off the road originally..) I'll wait until the next oil change, but other than a fatter o-ring, I'm not sure what to try.  I could maybe flatten the cover on some 600 wet and dry on my granite surface plate, but not sure that'd do much.  This is what the pan looked like when I removed the broken bolt.
(http://[attachment id=2 msg=142769][/attachment])
Title: Re: K75 Oil Leak and Clock Issue
Post by: Laitch on August 04, 2025, 02:35:32 PM
The OEM o-ring should seal if the cover isn't over-tightened; otherwise, it's liable to leak. The cover screws are torqued to only 6±1Nm.You mention flattening the cover. Is it warped? I wouldn't mess with it unless a straight-edge shows it is. I'd probably replace it if it was.

Verify that what you are seeing isn't oil coming from the circled port of the water/oil pump (photo below) that is then blowing rearward onto the cap during riding.

(https://motobrick.com/gallery/4/1601-040825142341.jpeg)
Title: Re: K75 Oil Leak and Clock Issue
Post by: Smudgemo on August 04, 2025, 03:06:03 PM
Definitely the cover from what I can see.  I stuck a Qtip in the weep hole and it's just some road grime.  The leak is getting worse, though.  I just remembered I left the bike in the drive with nothing under it and there was already a spot of oil an hour later with more ready to let go.  I gave the three bolts a quick check and they're not too tight, but maybe previously they were over-torqued which led to the broken bolt by the PO.  Maybe it leaked and he tried to snug things up a bit?  Who knows.

I guess unless there's another suggestion, I'll just keep cardboard under the bike until I do an oil change and can give the cover a better look.

As for the clock, I think I'll leave it for now.  Good vs Perfect and whether I want to potentially break something that's made of 33 year old plastic.
Title: Re: K75 Oil Leak and Clock Issue
Post by: frankenduck on August 04, 2025, 04:17:15 PM
Clock LCD: Segments can die over time. The clock only has two contacts: + and -. Recleaning them won't fix the LCD.

Oil cover: Add a light coat of RTV.
Title: Re: K75 Oil Leak and Clock Issue
Post by: Smudgemo on August 04, 2025, 04:49:25 PM
Works for me. 

Thanks fellas.
Title: Re: K75 Oil Leak and Clock Issue
Post by: Past-my-Prime on August 05, 2025, 07:06:52 PM
I find that changing the oil, the thing that is most important and takes the longest is making sure that the cover and o ring are absolutely clean and pristine, not a tiniest speck of grit or sand allowed!  Otherwise I also get an oil drip after changing the filter.