1990 r100gs driveshaft just got me home. Rear UJ almost collapsed. Have a new OEM one ready to go in. Looking at the Swing arm, I think I could add oil fill and drain holes. Has any one done this? Or should take apart every 20k Kms and lubricate the UJ bearings.

There are driveshafts available with grease fittings already added, that's considered to be the best approach rather than filling it with oil. The standard OEM shaft will do exactly the same thing at some point.

Be sure to replace the paralever pivot bearings when you take it apart. They rarely fail, but if they've been stressed it's better safe than sorry.

__________________
Grant Johnson
Seek, and ye shall find.
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Inspiring, Informing and Connecting travellers since 1997!
www.HorizonsUnlimited.com

I have done it to mine but I am not sure what if any difference it will make as the bearings are sealed so little or none of the oil will get in, you cannot lubricate the bearings in the original BMW shafts as they are stapled in only the rebuildable aftermarket ones which are worth getting.

I think the only plus of making it an oil bath is that the joints may run a little cooler - and that may certainly help, the grease inside the joint may last a lot longer if it's cooler.

__________________
Grant Johnson
Seek, and ye shall find.
------------------------
Inspiring, Informing and Connecting travellers since 1997!
www.HorizonsUnlimited.com

The weakness of the shaft is something that I have learned about since buying the bike. I bought an OEM replacement shaft when the EURO exchange rate was favorable, and intended to carry this with me as insurance. Unfortunately it looks like my original shaft in now not rebuild-able, as the yolk on the shaft leading to the rubber cush drive (rubber-filled join) is in a bad way. I guess that I need to try and find another shaft to rebuild with grease-able UJ's - looks relatively straightforward once I spec the correct UJ.

I bought some Nushings for the pivot. Easy to fit and should do the job. The Swing arm bearings were OK, so I have re-greased and put back in. Hopefully they still can "breathe" through the bearings - I used marine grease that is nice and sticky, the same as I use for the steering head bearings.

Thanks for the tip Mark. I see your point. Think that I will give the new UJ's a good squirt of 80/90 (for peace of mind) then assemble as is without trying to run in oil. I feared the boot tearing and dumping the oil out on the rear tyre.

Would a shorter shock help by relieving angle induced stress? I have read that this could help. I intend to use this bike fully laden, 2-up, mostly asphalt. I would like to visit my son & family (lake baikal) on the bike, then take a trip down into Mongolia, so I need a bike that I can service & repair on the way, that can cope with a variety or road types. This is why I bought the r100gs and shall spend the next year or so sorting it out and getting to know it.
It is a good bike.

Thanks for the help

Yes a shorter shock helps a lot in my opinion, I have had one from an R100R on mine for over 20 years and 120,000 miles, that is 200,000 km in new money, I also fitted one to Tiffany Coates' GS around the same time and we have both had far better mileage out of our driveshafts than most people get.
The GS is a good choice for two up touring, better than the G/S, just ask my regular passenger who will back me on that.
The airhead section on advrider is an excellent source of information, although ask on there and you may get me answering anyway, there are several knowledgable people on there who know just about everything about airheads between them, my only critcism of some of their answers are that they are not always relevant to using the bike for overland travel.
https://advrider.com/f/forums/airheads.85/

Doesn't the paralever driveshaft has a rubber shock/torsion absorber? The oil won't do that any good. Or the rear gaitor.
I carried a spare UJ but never needed to fit it. I probably still have it but I think they're readily available from bearing shops.

I have run mine with oil in it for several years without ill-effect, modern materials are pretty good at resisting chemicals, the rear gaiter is presumably made from the same material as the front one which is made to run with oil in it on other models.

My GSPD did 50,000 miles on its first shaft. I had it replaced as a precaution, although found it was in very good condition. Second one has done 60,000, and seems fine. I've got Ohlins rear shock. Never carried a passenger. Perhaps its just luck. It'll be checked again at the nexr service very soon. Will report back then.

One possible reason - maybe getting the Ohlins set up just right helps. I spent quite a lot of time tweaking it, and can adjust it for different loads.