Drive Shaft Questions

[Freelancer]

First, Yes, I've read through Ducks wonderful Splinetology thread. :2thumbup: It is a very good primer on Brick spline issues.

:hmm: However, my questions go beyond what has been covered in that and other threads so I decided to ask them all here.

My Questions are:

1) Is there a way to replace the splined ends that are connected by the u-joints? What I am asking here is that if one end of your driveshaft suffers a spline failure but the other rest is good, "Can you remove and replace that end with a replacement part or are you stuck ordering a whole new drive shaft?".

2)Are there alternative options that can be swapped in? (Is it feasible to shorten and fit K1200rs or R100rs shaft.... or are the splines different?)

3)What is the service life expectancy of a well cared for K-bike Paraleveler shaft that has been well cared for but sees high load usage?(I know that the mileage will vary upon conditions and riding style, just looking for a ball park figure.)

and finally(for now)
4)When buying used on Fleabay or Dregslist, "What should I be wary of?". I understand what to look for on the splines, but sometimes pictures can be misleading.

Case in point, I found a shaft that came off of a high mileage bike with a final drive that was junk. The photos of the drive shaft look good but with what appears to be some isolated deformations of individual splines. It is here that I would like to call upon the combined experience of my fellow brickers to help me spot issues I might be missing.
 
I've posted the pictures of this shaft below and now ask, "Do you think it looks good or if the seller might have used spray paint to hide some problems?".

Thanks,
Freelancer

[detbmw]

When I bought my K75S, the drive splines where excessively worn. It appeared that they had not been properly maintained. My first move was to call Anton Largiader in Virginia (Uber BMW Motorcycle Mechanic and he rebuilt my oilhead final drive a year ago). He knew of no one in the U.S. who repairs brick drive shafts. He was willing to take my final drive apart and send the pinion shaft to Oregon (I think to a BMW dealer) who would rebuild that one piece. His recommendation for the drive shaft was to buy a new one.

I continued to search and found Bruno in Canada. He rebuilds the pinion shaft on the final drive and also the drive shaft, uses a harder metal than the original, extends the length of the spines by 35%, and adds a grease reservoir in the drive shaft. If the upper portion of the drive shaft needs replacing/rebuilding, he can do that as well.

It cost me $800 plus shipping. Excluding the shipping, I felt the repair cost was close what I would have paid for the other option. Now I have a better-than-new setup on my brick.

I certainly don't know everyone who repairs bricks, but as far as I know, Bruno is the only person who repairs brick drive shafts.

[Freelancer]

@detbmw-

Thanks for the info on bruno. It looks like 800-ish dollars any way you go. I do like the idea of re-using the shaft with upgraded spline ends.

Quick question to you and others.
"Does the driveshaft pictured in the op look serviceable or does it look like it is damaged under the layer of black?

Thanks,
Freelancer

[detbmw]

It looks to me as if the tips are rounded and there is a slight mountain effect on some of the splines. That is just my opinion - it could just be the angle and the lighting that makes it look that way.

I have learned the hard way, you are risking your money whenever you buy without a return policy. Although I have always had good results with the MOA flea market.

[wmax351]

When I bought my K75S, the drive splines where excessively worn. It appeared that they had not been properly maintained. My first move was to call Anton Largiader in Virginia (Uber BMW Motorcycle Mechanic and he rebuilt my oilhead final drive a year ago). He knew of no one in the U.S. who repairs brick drive shafts. He was willing to take my final drive apart and send the pinion shaft to Oregon (I think to a BMW dealer) who would rebuild that one piece. His recommendation for the drive shaft was to buy a new one.

I continued to search and found Bruno in Canada. He rebuilds the pinion shaft on the final drive and also the drive shaft, uses a harder metal than the original, extends the length of the spines by 35%, and adds a grease reservoir in the drive shaft. If the upper portion of the drive shaft needs replacing/rebuilding, he can do that as well.

It cost me $800 plus shipping. Excluding the shipping, I felt the repair cost was close what I would have paid for the other option. Now I have a better-than-new setup on my brick.

I certainly don't know everyone who repairs bricks, but as far as I know, Bruno is the only person who repairs brick drive shafts.

My k75 has a shaft and rear end from bruno. Impressive machine work. No wear in 15k miles. Highly recommended.

If you are looking for a high ratio FD unit, I would be interested in swapping my 3.2:1 monolever, disk brake one for one of the lower ratio ones in similar condition. High ratio gives quicker acceleration.

Paralever sounds like there are almost no issues with, in terms of the splines.

[CRASH]

I see a couple of notched ends on the lower image .. I would I would probably replace it if it were mine.

@detbmw-

Thanks for the info on bruno. It looks like 800-ish dollars any way you go. I do like the idea of re-using the shaft with upgraded spline ends.

Quick question to you and others.
"Does the driveshaft pictured in the op look serviceable or does it look like it is damaged under the layer of black?

Thanks,
Freelancer

[detbmw]

I have learned the hard way, you are risking your money whenever you buy without a return policy. Although I have always had good results with the MOA flea market.

I should have said, you are risking your money whenever you buy ONLINE without a return policy or from an individual.

[frankenduck]

IMO, those don't look TOO bad. Keep them well-lubed and you should be good for another few 10,000's of miles. 

Riding is more fun than worrying,

[Freelancer]

Thanks guys, the info that the drive shafts not only can be repaired but also improved upon was really helpful.

Also, thanks Duck. Your comments on the pictured drive shaft gave me enough reassurance to go ahead  and pick it up. It was only $59 with free shipping. I'll send it off later this year to be rehabbed for my projekt bike.

Next question,

How much play should there be in the driveline? (When the bike is gear,"How much should the rear wheel turn stop to stop?".)

Later,
Freelancer

[frankenduck]

There should not be any play in the drive shaft but it's normal for there to be some in the transmission - a few degrees at the rear wheel when in gear.

[Freelancer]

Thank you for the correction.

Quick clarification: By a few degrees...Could that mean about 6- 10 degrees? My bike has about 1-1.25 inches of play when in gear.

Thnks,
Fl

[frankenduck]

Never bothered to measure it but that sounds normal to me.

[detbmw]

Thanks guys, the info that the drive shafts not only can be repaired but also improved upon was really helpful.

Also, thanks Duck. Your comments on the pictured drive shaft gave me enough reassurance to go ahead  and pick it up. It was only $59 with free shipping. I'll send it off later this year to be rehabbed for my projekt bike.

Next question,

How much play should there be in the driveline? (When the bike is gear,"How much should the rear wheel turn stop to stop?".)

Later,
Freelancer

If you send the driveshaft to Bruno, call and talk to him first. Since he extends the length of the driveshaft, he may have to modify the piņon shaft as well.

[frankenduck]

It's a 4V drive shaft.  A U-joint will blow up long before the splines wear out.