Some food for thought on R100/80GS driveshafts

[harvey]

I've just had some work done on my R100GS here in Bangkok by a guy who has been working on Beemers for over 25 years and seems to know his way around them pretty well. My bike's just topped 40,000 miles so I've spent the last 5,000 miles waiting for the driveshaft to go pop. I mentioned the driveshaft to the guy and he told me that over here they 'lubricate' the driveshafts which prevents the universal joints from seizing.
Basically, if you look at the universal joint bearings there is an O ring at the end of each one. Apparently when the UJ gets hot, the grease/fluid inside the bearing thins and works its way passed the O ring, resulting in a dry bearing which eventually fails. To prevent this, you gently lift the O ring and inject oil (Presumably transmission fluid) into the bearing until it is full. Then grease the UJ to keep it lubricated and bobs your uncle.
As I've not heard of this trick before I have no idea if it works, but it sounds better than paying US$400 for a new driveshaft! I got him to do my driveshaft because I figured I had nothing to lose, so I'll let you know how the bike fairs.
Anyone else heard of this little trick before?
Harvey

------------------
no pipe, no slippers
www.chasingthesun.org

[Sean Kelly]

An interesting idea...

For what it's worth, one source suggested that UJ wear would be worse if the drive shaft splines aren't properly greased.

Apparently, if the shaft doesn't slide in/out smoothly as the wheel moves up and down, shock loads are transmitted up to the UJ.

Can you let me know the details for your chap in Thailand, I should be there on my GS by Christmas.

------------------
Sean

[p_luth]

dear harvey!

I admit lubricating the bearings of the driveshaft sounds like a good idea... I actually had it done by Mr Yut (it's the same guy, isn't he?) in Bangkok last year- everything sounded pretty good. Nonetheless the shaft broke completely later on the trip in Kasachstan, something like 20.000m later (with a total of less than 70.000 km on the shaft).... In my opinion this lubricating trick won't hurt, but it also won't increase the lifetime of the shaft all too much.

Anyway, have a good trip and don't forget carrying a spare shaft once the milage gets higher and the terrain gets rougher...
Greetings, Patrick Lüth
www.transasia.at


------------------

[harvey]

Thanks for that. Yes it was Yut who did the work. He reckoned that you need to lubricate the bearings every 10000km or so to keep it smooth.
Harvey

------------------
no pipe, no slippers
www.chasingthesun.org

[dc lindberg]

How did it go ?
What option did you chose in the end ?

I poured Omega 690 80W/90 in the shaft of a K75 back then (2001) - that bike still has the same hypoid in the shaft some 30-40 000km later and in the hands of a new owner.

The "old" beemers had hypoid "bathing" shafts - they "never" broke (or very rarely). Why did BMW drop a working concept ?
has anyone tested pouring hypoid or automatic gearbox oil in the shaft of the GS's ?

[Frank Warner]

The 'old' bm only had one U joint - at the rear of the shaft.

The paralevers have two - one at the rear and another at the front. They also have a rubber dampener to take shocks out of teh transmission line.

I know of people who have replaced the U joints with ones that have a grease fitting - they then grease the U joints every year ..

I don't think oil is a good idea inside the U joint bearing unles there was lots of it all the time .. much rather have grease as a 'one time' thing.

[Redboots]

Originally Posted by harvey

To prevent this, you gently lift the O ring and inject oil (Presumably transmission fluid) into the bearing until it is full. Then grease the UJ to keep it lubricated and bobs your uncle.

I think you will find the "bob" will pretty soon be your auntie if you do that.

It has to be grease and high temp grease. Use the same stuff you put in wheel bearings.
The grease has to be in the needle rollers. The "o" rings are shaped grease seals/retainers.
Slopping grease round the outside will do ziltch. The ONLY part of a UJ that gets lubed is the end caps with the rollers inside.

You wont get far on oil. The oil will wash what little grease you had in there, out! Trust me.
Start saving that $400

John