What I've learnt
OK once again thank you all for the great advice.
Special thanks to all who have volunteered help in one way or another with parts.
Here's what I've learnt so far, summarised for anyone who cares to read it. Of course, all of the information below has nothing to do with the R1100S transmission, which I know nothing about and in any case will not fit the R11000GS/R/RT.
Please correct me if I'm wrong, I'd like to try and get this all right so we can build up a reference of sorts.
The R1100R/RT/RS/GS M94/M97 transmissions all have the same gear ratios. The M93 transmission has different gear ratios from the M94/M97 transmissions.
Different final drives are used for different R bikes. The ratios are presented below:
R1100RS 31:11 (2.818)
R1100RT 32:11 (2.909)
R1100GS 33:11 (3.0)
R1100R 33:11 (3.0)
R850R 37:11 (3.364)
R850GS 37:11 (3.634)
2) Interchangeability (complete gearboxes):
All M94 and M97 gearboxes are interchangeable. M93 is interchangeable with M94/M97 but you'll get different ratios in the gearbox.
3) Interchangeability (internals):
M94 internals will fit M97 housings with modifications to input shaft and rear intermediate shaft bearings.
M97 internals will fit M94 housings with modifications to intermediate shaft bearings. Some M94s had the newer M97-type bearing here.
M94/97 internals WILL NOT fit an M93 housing.
4) Interchangeability (housings)
The M97 housing has thicker walls and a different finish so there will be some mismatch when the front case of an M94 transmission is bolted to the rear case of an M97 transmission. Opinion is that it is possible to mix and match M94/M97 cases.
There is no such thing as an M96 transmission.
Please add on as you see fit. I will try to refine this when I have more time.
MJ Gurunathan screwed with this post 10-16-2012 at 10:31 AM
Reason: Remove errors in M96 housing nomenclature