Quote Originally Posted by Grumph View Post
Clutch hub wear is a prime cause of lost travel on the lifter mechanism. Somewhere there may be a figure for endfloat - but less is generally better.
The 80's Honda fours are very bad for it as the alloy hubs wear on steel thrust washers. In extreme cases the back of the hub may need machining and a shim fitted. Wouldn't surprise me if high mileage Ducs suffer the same thing.
I got into the hub in the Winter Layup thread - the finding (in short) was that the hub was flexing on its own cush rubbers and also was possibly misaligned on those same rubbers. The cushes can skew on assembly, if one or two bind up when the hubs are fitted together. It also looks like Ducati have undershimmed its position, unless that's a consequence of the vertically split cases and the way that the gearbox shafts assemble.

The design simply uses a nut and washer as an end stop on the hub's motion away from the clutch slave. There's no stop on it moving back toward the clutch slave, but that isn't needed. Ducati may have wished to avoid yet another fiddly shim stack and simply allowed a generous assembly clearance.