Oil leak in 1100gs tranny: input axles rear seal

[Antti]

I`d be grateful for any tip for this job.

Bike is `95, with cable clutch and has some 120 tkm on the clock.
Last summer clutch started to slip mainly with fifth gear under hard acceleration.
As I was a bit in a hurry I just changed clutch plate and noticed that leakage comes to
push rod tunnel and goes from there to plate. I just cleaned all places and hoped it to last for a while.

Now after 11tkm I took it again apart and luckily plate is still dry, but some amount of oil
has leaked.

Tranny is on table, and I have new seals for both ends of input axle. And heatgun + hammer
Anything else needed or look after?

 

[DrFarkoff]

Later clutch pushrods have a felt washer halfway along the rod
You can just replace your old one with the later one

Also take the pivot on the clutch arm apart and make sure it is not sticky or notchy clean and grease it well including the adjusting screw

 

[bart2181]

Was changing just the clutch plate succesfull?i.m under the impression the whole lot has to be changed.only asking has mines slipping too.

 

[Tsiklonaut]

Looks too little milage for it but probably rear bearing of input seal is about to be gone. I've had two of 'em go with the same symptoms. Typical issue on the R1100s with M97 boxes, although yours is M93 or M94(?), unlike M97s those are kown to kick out gears, especially 3rd. Loads o' work to get it sorted since you have to split the box in any case

Edit: 150K is about when mine went first time as well.

 

[Welshman]

Later clutch pushrods have a felt washer halfway along the rod
You can just replace your old one with the later one

Also take the pivot on the clutch arm apart and make sure it is not sticky or notchy clean and grease it well including the adjusting screw

Suprised that later 1100's had the felt washer thing, as my early 1150 (mid 1999) doesnt have??

 

[Pekkavee]

This will help you in the orienteering inside the box after you open it.
What's inside the box
One other
I hope.

Pekka

 

[Antti]

Have You Tsiklo changed any bearings yet in those km's?

Thanks Pekka for the links, thread from advr was familiar.

I gave a wash for the tranny. Shines like new.
Its DAG / M94. Think that I've read thats the 'second worse' option or so.. and some one told that it must have been re beared already once or twice at 120tkm. Well, for me all bolts and split surface looks strongly untouched and it works very nice.

Couple next weeks are budgeted for our MC's christmas party preparation and need to work on few things on Xchallenge before that. As the party include two days fun on spikes

 

[Tsiklonaut]

Have You Tsiklo changed any bearings yet in those km's?

Yep, as told it was the rear-end bearing of the input shaft that's a common fault point on M97 boxes. On your M94 I don't know, but the symptoms are like mine when it leaks oil like yours.

I've repaired mine 3 times already. 2 times I was forced to do it on the road with limited tools and conditions in open-air.

1st time in Australia at around 150Kkm mark the rear gearbox bearing went with making huge noise. One Australian guy helped me out and let me use his tools, camp in my tent and work on my bike in his backyard (big thanks to Lance in Kalgoorlie), took me 3 days of work since I had a broken frame to fix as well:

<iframe width="640" height="360" src="//www.youtube.com/embed/lvAgaDol1dE?rel=0" frameborder="0" allowfullscreen></iframe>


2nd time in Mauritania, around 230Kkm mark with oil literally pouring out from the rear like yours, had to wait some 2-3 weeks for the bearing in Nouakchott, decided to do it in shorter route, took me couple of days to search all the whole city mechanics for a similar bearing and through luck I found one and installed this cheap Chinese bearing just to get me home back to Europe. Did the gearbox repair in my cheap hotel room's shaky table:

<iframe width="480" height="360" src="//www.youtube.com/embed/8PBvMnsiJUo?rel=0" frameborder="0" allowfullscreen></iframe>


Since I had to do it anyway (can't trust the Chinese) on the 3rd time I replaced all the bearings in the box as a precautionary measure + installed a new-design modifyed complete input shaft at around 250Kkm mark since I could do it in my own garage. The new design input shaft, that reduces the "bashing" effect to the rear bearing (so it's less prone to fail). This new complete input shaft can only be ordered separately from BMW. If you look carefully you can notice the obvious design difference.

See the end on the new is rectangular (old design is cone-ended) - the biggest difference that you don't see on the pic is the larger and deeper-recessed-into-shaft stopper-shim that has a couple of more millimeters of "bite" area on the new version so it is able to take the "punch" better from the gears hitting the bearing every time you accelerate/deccelerate and switch gears.

Hope this helps,
Margus

 

[Antti]

Thanks a lot Margus!

 

[Antti]

Here we go!

 

[Antti]

And theres that little f***er. I changed all seals once at it.

 

[Antti]

And all together

 

[Antti]

After few tanks tranny is still working okay.