BMW R90/6 gearbox restoration

[Grimsboy]

G'DAY Gentlemen,
                           I am in the process of restoring a 1974 R90/6 900cc BMW. Having stripped the five speed gearbox,I found a dog had broken off the central gear of the intermediate shaft assembly. I am describing the gear in this manner because in all the manuals that I have acess to this shaft is described as a unit and the gears are not individually identified. ( there are 5 gears and this one is central).
My problem is that I would like to replace the gear with the broken dog but have been advised that this is not possible because the gears have been assembled in such a way the it would destroy the shaft to disassemble it. Before taking any action I am trying to acess any information or previous experience on this problem so if anyone can offer any advice it would be greatly appreciated.
If a total shaft replacement is required can anyone advise on possible used parts.
In advance many thanks
Dennis

[L.A.B.]

It is true that the intermediate shaft and its components are only available as an assembly, and I'm not really sure that it can be successfully dismantled and rebuilt -or not?
It may be worth looking out for another decent used gearbox, as the same box was used for the 5-speed 600/750/900 /6 models and even the later /7 boxes up to 1980 are more or less identical, as they all use the same internal ratios as each capacity model had its own particular bevel drive box containing the correct gearing ratio to suit the engine size.  

You haven't mentioned where in the world you live, so that makes any parts supplier recommendations difficult unfortunately?

If you are the same 'Grimsboy' from the TOL website possibly you are in Australia?

The UK suppliers that I use and would recommend for new and used BMW parts are:

http://www.james-sherlock.co.uk/

http://www.motobins.co.uk/

http://www.motorworks.co.uk/

[Grimsboy]

Hi L.A.B
           just explored the websites you suggested and they look promising many thanks for that.
It does look as if a repair to the shaft is unlikly so as you suggested a used replacement will be the way to go.
I had hoped there may have been someone out there who had some experience with the same gearbox and had experience to share.
Many thanks. Dennis

[L.A.B.]

There's a couple of good BMW forums that I use, and someone there may be able to give you more specific information about your problem and how best to fix it?:

http://www.bmbikes.org.uk/Forum/

http://www.motobins.com/yabbse/index.php

[Grimsboy]

This information has been invaluable and is much appreciated . Having always worked on Triumphs over the years I am in foreign territory.
again many thanks.
regards Dennis