Hello,
This is my first post on this forum and I am looking forward to being a part of it. I just purchased bike #4- a 1985 K100RS with no less than 251k miles on it. The bike runs strong but has a bit of a rattle at idle. So, I am trying to learn whether it is the six rivet output shaft or the timing chain that is rattling. This forum is a great resource for information and if anybody can chime in and help me identify the noise, great. Ideally I would like to find someone in the WI area (shop or private person) who can help with input spline lube, too. I am not yet comfortable tearing that deeply into a bike. My other bikes are a 1976 R60/6, 2002 1150rt, 2093 r1200cl.
Thanks!

Welcome

The splines seem intimidating since you have never done it before. I feel this bike has been designed to be simple to work on for a non mechanic. After you do it, you will be surprised how simple it was. With the help of a workshop manual the splines is a simple job. Try to locate the source of the sound.

Thanks for the words of encouragement about servicing the input splines. I'm taking in lots of information right now (Haynes, YouTube, forums, phone calls) about these service items. Let's see how easy it seems down the road.

After we  spoke on the phone it's good to see that you signed up here.

Doing the input spline lube really isn't that big of a deal.  It's just taking a bunch of things apart and putting them back together.  Everybody, myself included, is a bit leery of doing their first spline lube but it really doesn't take more than basic wrenching skill.

I can do a spline lube in about 4-5 hours but for your first one plan on a very long day or maybe over a weekend. If you have a decent amount of work space it's a good idea to line the parts up on the floor in the order that you take them off. Then just go backwards when putting things back together.

You might find this link useful: http://bit.ly/new2kbikes

duck wrote:After we  spoke on the phone it's good to see that you signed up here.

Doing the input spline lube really isn't that big of a deal.  It's just taking a bunch of things apart and putting them back together.  Everybody, myself included, is a bit leery of doing their first spline lube but it really doesn't take more than basic wrenching skill.

I can do a spline lube in about 4-5 hours but for your first one plan on a very long day or maybe over a weekend. If you have a decent amount of work space it's a good idea to line the parts up on the floor in the order that you take them off. Then just go backwards when putting things back together.

You might find this link useful: http://bit.ly/new2kbikes

As was said by others, these bikes are easy to work on if you take your time.  First day I had my first brick, I had to pull the transmission apart to tighten a loose grub screw. 

Get a box of ziploc sandwich bags and a Sharpie pen.  As you take the bike apart, put all the little parts from each section(rear shock, final drive, etc.) into the bag and label it with the Sharpie.  Also, I have my laptop handy so I can refer to the MaxBMW parts fiches to help identify what fasteners go where.

Welcome Allemandemusic