possible cardan problems R100gs...

[Zimi]

Hi! I'm in Uzbekistan on a R100gs, and my back wheel has some hard spots when I turn it with the hand. It makes some "klonk klonk" on the side of the gearbox when i turn the wheel by hand. When I ride I don't feel anything special.. The oil level in the gearbox and on the back (don't know the name in english) are ok, I just changed the oel.. There is no radial play with the back wheel.

What should i do? Continue riding like this? Here in Uzbekistan, I think it's difficult to find a good mechanic... and I don't know which parts I need...

Thanks for suggestions... I should ride 3000km to be back in russia, then I have no problems with visa (have a 1year multi entry) and could wait for parts...

[chris]

Hi Zimi
I presume the bike is on its centre stand when you hear these sounds? The angle of the drive shaft to the gear box output bearing is very steep and it may be that the drive shaft is knocking on the inside of the swing arm.

I'd suggest the following:
1. Push the bike down the road with no motor running and listen, or get somebody to push the bike while you crawl with your ear next to the back of the gearbox. If there is no sound, you should be ok (I had the same symptoms as you and when I crawled next to the bike there was no noise).

Just to really check I took the driveshaft off and put it on a lathe to see if it was out of allignment: mine was ok. I did this because I had just replace the U-joint 500km before and I was concerned. In this case I was just being paranoid.

If you are still not sure:

2a. Try to inspect the front U-joint by pulling back the rubber boot and spinning the wheel.

2b. remove the drive shaft and inspect both u-joints. A car/truck mechanic replaced mine in Ecuador. Any good mechanic can do this: car/trucks have many u-joints, just usually a lot bigger than on a BMW bike.

If you need a new u-joint, the part you need is easily available in Germany. I don't recall it was very expensive either. I'm sure you can search on google.de or search/post a question on a German speaking BMW forum.

The German for universal joint is Kardangelenk.

If your gearbox is losing no oil and there is no oil in the swingarm, then your gearbox output bearing and seal are probably ok.

Good luck
Chris

[Zimi]

Hi chris, thanks for your answer!!!

no I'm not loosing any oil and had the gearbox completed rebuilt before my trip (new bearings and sealings). I will try, but I think it make some noise when I push it, maybe a little less, but still. But I don't feel anything particular when I ride it...

Will keep in touch

[chris]

Hi Zimi
If it is still making a noise when pushing it, I would look very very carefully at the front u-joint and where it connects to the gearbox and the kardan.

Before I replaced my u-joint I had noises too (don't remember exactly what kind, but something made me stop and return to the town I had just left (Locha in southern Ecuador). A man in a car took me to his mate's garage. He spoke English and he did everything for me.

Luckily I spotted it in time and replaced it before everything (u-joint and 2 holes/mounts on kardan) broke completely. This prevented the hole (on the kardan) that part of the u-joint fits into from breaking off completely. On mine it was only cracked a little and was welded successfully. Then the new U-joint was fitted.

Also if the u-j breaks completely while riding you'll have a kardan smashing about the inside of your swingarm for the time it takes you to stop the bike.

If it is the u-j that is the problem, then getting one small u-j posted and fitted will be much cheaper and easier than a whole new kardan with 2 u-js.

Let me know how you get on.
cheers
Chris

[dc lindberg]

Do not like "klonk klonk"...

Have you used a long screwdriver, tire iron, or what ever of solid material as a stetoscope?

Locate the sound!

It is not likely that anything inside the gearbox broke - but it is prudent to rule-it-out.

Just grasp across the rubberboot and feel how the U-joint moves. If anything feels a bit "not right" - unfasten the boot and inspect.

What I fear have happened is far worse... a damaged bevel... sounds like it comes from the gearbox, but it really steems from the bevel (final drive).

See, I suffered just about what you describe a couple of years back.
- put the bike in neutral on soft smooth level ground. Pull and push the bike backwards and forwards gently; any kind of non-smoothness from the bike will indicate drive-train damages -

Perhaps this link is fully open - so that you can see what happened to my final drive:
Svenska BMW MC Klubben • Visa tråd - Tandläkare sökes till slutväxel


Summation:
- rule-out gearbox by using a "stetoscope"
- check the u-joints
- beware of final drive internal damages, like broke teeth and bearing failure.

[Magnon]

My experience is that we noted a small vibration at certain speeds between Springbok and Capetown. By the time we arrived at Johannesburg (about 3000 miles) it was more consistent but not bad. We flew the bike to Luxembourg and after 800 miles in France it eventually packed up in Rouen. I can't say if it's the same problem as your's but I would say that if you don't notice the problem whilst driving continue gently and arrange for a new shaft to be awaiting you at the next major city or BMW garage. Keep hold of the faulty part and get it serviced/repaired by a specialist