gearshift mechanism R100S

[rider1D]

On the road here in W.Virginia heading to Michigan but finding neutral and getting clean shifts became harder and harder. I finally looked at it and the whole foot shift lever is extremely floppy, as in big movement from side to side. This is a R100S made in 1979 where they went to the new linkage rod with the rubber boot and the two spring clips inside. However, I had that come loose once before and that is not what is happening this time..

In this case the shift lever is going up and down like it should (1st to 2nd to 3rd, etc.), but it is loose laterally. You can actually shake it and it will move left to right. The toe rubber on the selector probably moves an inch or more side-to-side. Meanwhile, where the Allen bolt goes through the pivot point looks from the outside like it is missing a cap or maybe a nut or something. You can actually see the threads on the female mating surface to the Allen.

We cant figure out what's missing by looking at the exploded diagram of the microfiche (MAX BMW).

It doesn't appear to be getting any worse, but finding neutral, etc. is difficult.

Can anyone please help?

Thanks in advance,
Neal

 

[20774]

Neal -

Sounds like to me the shaft seal #9 has given up the ghost:

http://www.realoem.com/bmw/enUS/showparts?id=0394-USA-11-1978-2474-BMW-R_100_S&diagId=23_0256

When you say "laterally", are you sitting next to the bike on the left side and the movement is fore-aft?

Here are the parts that are external to the transmission on the left side.

http://www.realoem.com/bmw/enUS/showparts?id=0394-USA-11-1978-2474-BMW-R_100_S&diagId=23_0269

 

[QUICKDRAW]

I'm having a similar problem with the shift linkage on my R100RS. The end of the shifter moves latterally (in /out) about an inch at it's most forward point. It appears that tightening the flat head allen bolt at the rear ball joint (the pivot point) would take up the play and solve the problem. However this bolt is threaded into the tapped hole from the inside and access to the allen head is impossible. Removing the entire foot peg and shifter linkage seems to be the only way to fix it. Am I on the right track?

Thanks in advance for any suggestions.

 

[Darryl Cainey]

The only thing the seal does is stop oil from coming out.

Tighten the bolt in the shifter.

 

[thomasgspd]

I have a similar issue with my 1978 R100s. I removed the entire foot peg to do the repair. the problem to me seamed to be that the shift lever has worn out over time. A replacement seems to be hard to locate or very expensive, so i just added a shim to the head side of the bolt to tighten it up. the bolt is a stepped head type so it tightens up while letting the shift lever move. i still have a little play in the lever but i think it will improve the shifting, and i can always add more shims after time.