Yep, 20 mm diameter, can check pitch tomorrow afternoon if needed.
A butchered nut, but you got it off with a peg spanner ?
If cleaned up it could go back on with your peg spanner, 33/36lbs/ft.
You know of the outside marking.
Look at the nut, a picture would be good, notice the bevel or chamfer, chamfer to outside washer is the correct way to fit it.
How were the clutch basket finger internal surfaces, dirty, a centrifugal crap trap.
How is the balance shaft adjustable adjusting quadrant, the shaft dot and it's position ?
Whilst the cover is off, flush out the sump floor and kick starter shaft oil trough.
You changed the oil filter, much black death on the filter cover floor ?
Don't misplace that thin steel washer on the filter.
You can use top gear and rear brake to lock engine to torque the clutch nut, notice the small alloy posts on the clutch drum, honda was thinking of a lock washer/tab during Thier many many many committee meeting bad hair days...
You know how to make gaskets ?
Make sure clutch "mushroom" is properly in place before refitting cover, and kick starter spring and "square" if fitted with kick starter...
