We got the clutch assembly off. It required a bit of heat and a big rattle gun. Very tight.
Before dissembly of the crankcase, we noticed the shaft could be moved up and down about 250 microns or so! The slop turned out to me between a sleeve an the alloy casting around the output bearing. We don't know why the alloy has a 2mm wall thickness sleeve here, it is certainly original. But the problem is between the sleeve and the surrounding casting.
The main bearing will be replaced. However, the output bearing looks like a special Stihl part. I will check to see if there is an after market replacement.
I'm wondering if common sealed bearings will servo ok in a 2 stroke crankcase and take the crankcase compression. Anyone know? I seem to recall seeing plain sealed bearings in other two strokes like mowers etc.
edit:
I have pictures to post, but I don't know how to do so on these forums yet.