In my page about the K100 renovation, I am talking about the rivets geting bad on the ouptut shaft.
A picture is worth 100 words, but a video is worth a million words.
Here is what I found on Youtube. Click on the video....

Aha, they are mine. Nice to to find your own rivets on this nice forum...
I put a 12 rivet version in my k100rs and it rides great.
Thanks for the information and lots of foto's i found on your site.
It realy helps me visualizing the problem.
Succes with your forum.
Greets,

Eric, the Netherlands, Europe.

Eric,

Welcome to this forum and thank you for sharing this video on Youtube.

Bert

I have finally began my restoration of a '85 k100. I thought I was in pretty good shape. I should get my new con rod bolts and water pump in on friday. Well today I read the manual a few times, and thought I would reinstall the output shaft and everything was going to be just fine.
I had it all assembled and a few hours later, I was wondering if I had to pre-load the small gear. I honestly cannot remember this its been a very long time since I took it apart. The book didnt say anything about this preload, but another site did mention it. I remember it popping out I think, once I pulled the pan off, but that was a few years ago.
So I took the upper oil pan off again and removed the output shaft, and I do believe I have the worn spring issue. I have no choice but to pull it apart and check at this point in time. I can move the idler gear back and forth some. This is really disapointing to me right now. I had to peen(light scoring to raise some metal up to allow a tighter fit for the bearing) the surface of the bearing housings to prevent further spinning of those bearings. Its just becomming a disapointment once again for me.
I would forgo replacing the spring if I knew for sure I had to preload the idler gear, I guess with a single tooth twist essentially tightening up the spring but then I would hate myself. I would just like to get it back together, and running. I do not know if it will.
In the summer of '95 a nest of Dirt Dobbers moved into engine some how, and filled everything they could with dirt.
Im trying my best to avoid scrapping the project. It was a wonderfull bike to ride. I have picture of the processes I have been taking. and maybe this will help me some with the issues I'm currently having and may or may not run into during this.
And if your wondering, yes, I did take it completely apart.
Thanks for any input or encouragement.
Phil

2:21am, I re removed the output shaft and took it apart and sure enough, extreme wear on the retaining ring, im still wondering about the pre load, but im betting once I get a new spring in that will be a no brainer.

Gezar wrote:

2:21am, I re removed the output shaft and took it apart and sure enough, extreme wear on the retaining ring, im still wondering about the pre load, but im betting once I get a new spring in that will be a no brainer.

Phil, as you say, it will be a no brainer.
The preload of the idler gear is less than half of a tooth. This is a 2 people job. One twist the idler gear to preload, and the second person will clamp it in place with a C clamp or a wise grip.

As indicated on my K100 rebuild page (http://www.bmwons.ca/k100/k100.htm):
Caution: When re-installing the output shaft, put some loctite on the outer race of the bearings to avoid them to spin free in the crankcase.

I'm new to this post. I'm on a 85 rs 140k in. Love the bike. Ended last trip thru Utah in back of a Duramax truck. 6 rivet output shaft failure. Plan to replace with the improved 12 rivet 86 version. I heard the knocking... for a few months before this failure. I have studied my Clymers and have been reading everything I can before getting into the repair. Seems pretty simple.... Is there any extra knowledge I need to enable the perfect repair. I plan on also working on all seals, checking timing chain, oil/water pump and taking a look at bearings. Thx

This is an easy job. I have few pics in my K100 rebuilt page.
Since your rivets failed, you should check that not any pieces went into the bearings or got stucked somewhere in the cranckcase.
It would be a good time to overall you oil/water pump.
Check for a tutorial in the download section.
If you have any question during the repair, post it and I will reply.
I have experience doing this job.

Bert

Are any of you aware of a way to look at your rivets without major surgery? Maybe by removing the filter and using a mirror or similar? I'm starting to doubt the output shaft, but would like to be certain before I do the major bits, as I have to do it in the open.

Sorry, but I don't think that you can check the rivets without at least remove the gear box. When the gear box is removed, you may be able to check the slack on the output shaft.