OK, now I know why no-one has attempted this before!
First thing I did was download some pictures of both bikes and worked out all the geometry, whilst some of it differs by a couple of degrees, this could just be down to the M696 arm being a little longer.
The arm fits the engine no problem, same width and the pivot spindle is the same diameter, there is exacly the right amount of space at the end of the spindle to fit the circlips back on, so all good there.
The rear wheel spindle on the 750 is the correct length but is too skinny though so either I get a M696 spindle and new wheel bearings, or use conical spacers to centre the spindle in the swingarm? I think either would be viable and safe.
In order to accommodate the frame, I had to file back some of the swingarm where the the bolt goes through, no biggie here as there is a steel threadsert which I ground back to which gives plenty of space for the shock.
Now comes the really hard bit, attaching the top of the shock to the frame. After a lot of measuring and re-measuring, coming up with different solutions, I thought that overkill is probably the best approach so designed a bracket and used 6 gauge hardened steel to make up a bracket to be welded to the frame and incorporate the original top bracket in case it doesn’t work and I can undo my work without then having to reposition the original brackets.
So, this is as far as I have got, the swingarm fits the engine, the original shock fits without hitting the frame and I have a mocked up bracket.
All that is left to do now is put everything together, check the final position of the new top bracket and then weld it in place.
Fingers crossed that it all lines up as it has taken days and days to get this far!
