My new (old, it's 17yrs old!) GS that is such a pleasure to ride and so very yellow came with three oil weeps that the PO must have unaccountably neglected to mention.
Number one and two were my kind of fixes: judicious fiddling with slim spanners of the stubby variety revealed that PO just hadn't been able to tighten bolts properly. Hmm, not entirely confidence inspiring.
Number three was from the rear of the gearbox where BMW thoughtfully located the neutral switch below the waterline. Behind the switch lurks an oil seal, about 18mm in diameter with a 8mm shaft sticking out of the middle.
Haynes advises removing rear wheel, swing arm and shaft drive. Generally a super pig of a job.
Yours truly spent a while on the garage floor (no, don't mention the hydraulic bench - there's really no need!) and thought of plan B. Up on my 8" home made bench and CAT and silencer off (itself a battle with low-quality, modern BMW fixings) and I could remove the switch and see the leaky seal. With the help of thin screwdrivers, ample profanity, and some restful cups of coffee, I butchered the old seal out, cleaned it up and used a socket and tyre lever against the unremoved swinging arm to drive the replacement in. And it worked. Perfectly. Sounds simple but this was work spread over a day with breaks for this and that, like remembering what it feels like to have your head above your feet!
How exciting! There was a ten minute stage with a fully butchered seal when I thought it might not succumb but once the spring was extracted from the seal I knew I'd won.
Happy days. I'm thinking about an experimental removal of the exhaust stub bolts next but I think I'll ride it for the summer: I can envision the potential for the 'snap' of doom. Maybe I just won't bother!