M30 Drive-side end float

I know very  little about setting up an OHC Norton. On the OHC  Ducati motors I have worked on the crank  is  set up with zero end float to avoid  loads being transferred  on to the bevel drive  gears  or  having a slack  noisy cam drive.  " a few thou"   would be my guess. On a Norton the timing side crank is clamped in position  so it is not so critical ,however should the main  bearing fail in use then a small clearance would help avoid  side loads being put on the cam drive or con rod.

When I assembled my engine, I aimed at absolute minimal end float before the timing side mainshaft nut is tightened, less than .002". My reasoning is that the only thing remaining floating once assembled is the drive side roller main bearing inner race. I made a spacer between the 2 drive side bearings to achieve this. As the cases expand when they heat up, that endfloat will increase and the mainshaft can still move in both the drive side bearings to accomodate that float. Maybe I should say it's the bearings that are floating on the mainshaft. So far, so good.

I would suggest you email Barry Stickland the club ohc technical specialist. He has rebuilt numerous inter engines and in the case of mine did a very good job.