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Old 05-26-2012, 07:27 AM   #1
MJ Gurunathan OP
Joined: Apr 2008
Location: Singapore
Oddometer: 10
Cracked R1100GS Transmission Case

Hi there everyone.

I have a question that I would like to ask. I ride a 1994 R1100GS that has been absolutely brilliant till... now. You've probably guessed by reading the thread title that the transmission housing (where the RHS swing arm pivot threads into the case) is cracked.

This happened when I sent the bike in to my local dealership for a clutch replacement; apparently the pin seized in the threaded hole; in an effort to remove it the technician used a breaker bar and a cheater bar on top of that and *crack* went the transmission housing.

Here's a picture of the damage:


I'm not sure why they didn't stop and drill the pin out, but that's a story for another day. The dealership will not pay for the damage (despite much slamming of palm on table) so I am left to fix this problem myself.

Here are my options and my opinions on them:

1) Purchase a used transmission: the workshop supervisor tells me that the following transmissions will fit my bike: M94 or M97. I've read Mr. Anton Largiader's website and this seems like a good solution, but I am having trouble finding M97 transmissions in good nick. Used transmissions are not available where I live (I'm in Singapore).

2) Purchase a transmission housing and use the internals from my transmission: this seems like the best thing to do. This will also allow me to rebuild my current transmission, increasing reliability and improving the shifting (I have a problem with the bike skipping from 2nd to neutral and engaging first from neutral without feathering the clutch).

The problem with this is that I do not know which transmission housing will fit the internals of my current gearbox. As far as I understand, the housings from all years are externally the same, but the internals differ depending on the type of input shaft and bearings used.

3) Weld the cracked area and carry out an insert-repair on the threaded hole: this seems do-able, but I have to make sure that the work done is tip-top or else I'll end up with more problems. There is also the possibility of the case distorting during welding.


Given that my GS was produced in 1994, what sort of gearbox housing would fit the internals of my current gearbox?

Are there any other solutions that you would recommend?

I appreciate any and all advice; I'm hoping to compile a little gearbox FAQ and maybe an interchangeability matrix of sorts, but I am short of information... hence my post.

Thanks in advance for all your help!

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