Drive Shaft failure - Options?

[rmarkr]

Well, my K bike let me down. It is a 91 K100RS with 50k on the clock. The forward cardan joint failed completely, without any warning that I could discern. About 5k miles ago I lubed the splines, and all looked good.

What are my options - new, used or any hope of a recon unit?

Any suggestion on why this failure? It appears that the joint got very hot - the remaining cap in the drive shaft section is blue. The good news is that the splines and final drive seem OK.

By the way, the MOA arranged my tow promptly, and the tow guy was a biker and had the routine down pat. I got the first 100 miles free (of 160 miles) then $3 a mile.

 

[motoedde]

I feel your pain...one word...Bruno....contact him over email...

http://www.brunos.us/

His can rebuild both the shaft and the pinion on your final drive if necessary. A much cheaper option than buying new...unless you happen upon a good used unit.

A rebuilt unit will last you much longer than a new unit.

 

[roy]

may want to confirm that Brunos can replace the yoke on the drive shaft. I believe typically they just replace the u-joint and not the complete yoke. New drive shaft was cheaper for me than having a new u-joint installed.

Roy

 

[rmarkr]

Thanks guys. I'll give Bruno's a call. The list price for a new shaft is $700 - ouch!
I thought only Guzzi drive shafts fail! One clue to this issue is that I replaced the rear shock, and initially had a stiffer spring. I then adapted the shock (YSS) to take the OEM spring. Perhaps the change in swangarm angle set it off, although it must have lost its lube to fail.

 

[motoedde]

may want to confirm that Brunos can replace the yoke on the drive shaft. I believe typically they just replace the u-joint and not the complete yoke. New drive shaft was cheaper for me than having a new u-joint installed.

Roy

Give Bruno some pics over email BEFORE you call...so he can see for himself...whatever he recommends go for...he might have a spare shaft sitting around and can forward that to you...

But its historically better to have both the pinion and drive-shaft splines rebuilt and mated together. It might cost you more right now, BUT it will be cheaper in the long run...PLUS you have the time to do NOW.

HTH

 

[98lee]

The list price for a new shaft is $700 - ouch!

It's items like this that really make http://chicagobmwmotorcycle.com/store/ valuable.

CALL them.

Ask about 20% off. $553.46.

See what kind of time frame (could be several weeks).

 

[rmarkr]

I ordered a recon unit from Bruno - he has one on the shelf. $450, less $100 if the core can be used. His recon unit can be lubed (removable grease nipple) and the cups are retained with circlips, so they can be replaced. I like the idea of being able to lubricate and service the joints.

Dealer prices for new:

MAX, A&S $692 (list)
Bobs $660 (in stock)
Chicago $553 (Thanks Lee) but not in stock -1 week

Pocket is feeling a bit lighter.

 

[58058D]

Key to reinstalling is to be sure you balance the shaft as far as the orientation of the U-joints. Do a search or PM Paul Glaves. If I remember correctly, one of the most common reasons for failure is an unbalanced drive shaft.

 

[rmarkr]

Drive Shaft Alignment

View attachment Drive Shaft.bmp

Thanks Jim
This is how it was installed. From the parts fische.
Is this correct - Paul?

 

[58058D]

That is correct. Nice to see the diagrams are correct. I neve knew if my failed K11 shaft had been out of balance or not, but after installing the replacement correctly, it was noticably smoother.....