Hi. I have 1993 K1100 LT 200 000km +
It's been a winter project. This forum helped me a lot. 
But now I'm having a problem that I can't find answer myself. 
I have free play of back wheel and rattle sound, that I think is something loose in gearbox or drive shaft. Made some videos.
https://www.youtube.com/shorts/h-lgSHYdYRA?feature=share
https://youtu.be/LciUI2eNbK8
Did the listening with a screwdriver and that nocking is not from the alternator and I have no change with the clutch in or out. 
Any advice?

Did you remove the drive shaft?

Welcome Nakromanas

Take the rear off and check the splines, think you will find it there.

Nakromanas wrote:Any advice?

Welcome! I don't hear anything unusual from either your engine or transmission while the engine is running in your video. If it were mine, I would not worry about it, but I have a high tolerance for uncertainty. It just sounds like a normal Brick. I had my ears examined last August; however, I haven't had my head examined recently. 

You've shown that there is play in the rear drive. Bolt the wheel to it then grab each side of the wheel and try to wobble it. If it doesn't wobble, that's good. Don't get desperate about rotational play yet.  Have you any experience riding this moto? How long have you owned it and how long have you been a motorcycle rider?

Remove the rear drive, like Arlina recommends then take clear photos directly facing both the transmission driveshaft's splined socket and the rear drive's pinion gear shaft splines. Start a new thread in the Technical, repair and troubleshooting section then post your photos in it. It's likely that a triage team will then assemble to examine the photos and make diagnoses. 

92KK 84WW Olaf wrote:Did you remove the drive shaft?

Not yet. But will do. However biggest sound comes from around gearbox or clutch area. I can feel that there is not much of the clutch left there. It is adjusted.
Can the clutch make that noise? 
And what about wheel free play, where can i get any info how loose it suppose to be?

Your bike has a Paralever swing arm that has two universal joints in the drive shaft. There are two things you need to be sure of with it.

First, the drive shaft has two universal joints that need to be properly "phased" to prevent stressing them. Running without the joints phased will result in one of them failing, usually the forward one at the transmission end of the shaft.

The second is that the transmission end of the shaft has a ring that locks the splines onto the output shaft of the transmission. It's critical that the drive shaft be pushed all the way onto the output shaft, otherwise the shaft will not align properly with the swingarm pivot and the universal joint will hit the inside of the swing arm. This is not good as it will eventually result in problems with either the swing arm or the universal joint. It will also make a clicking noise as the wheel rotates.

Hello fellow BMW owners. My name is Dan and I am from the home of the Green Bay Packers. Loving my new to me 85 k100rs with just 59,000 miles. I have loved motorcycles since I saw my first one in my childhood. I have had so many motorcycles throughout my 51 years on this planet. 
My best friend is the previous owner and has had it over a decade. He and his family is looking into moving out of the State of Wisconsin to Arizona for retirement. Anyhow he was downsizing his collection of motorcycles and offered me first crack at the K100rs.

I love this motorcycle. Truly a classic. I am used to riding the big V-twins with loud exhaust and feet up on hiway pegs. 

I wish I would have owned one four decades ago and collected and rode these sooner. I don’t miss the rumbling ride or loud exhaust. I still have the cruiser but seldom take it out. I work on all my own motorcycles and have built a few choppers from the ground up and won trophies in the Radical Class at several motorcycle shows throughout my state.

I do have a few questions but I will save them for another section of this forum. 

Thank you for allowing me to join this page and I look forward to learning as I go.