RE: Let's talk thread lock (and shimming)
I usually have to have shims inside and outside the clutchbell. If there is a washer behind the capscrew in the crank, make sure there is virtually no movement between the outer clutch bearing and that washer/capscrew. Also to note, tolerances expand when those parts get hot. 1mm is a LOT of play and is excessive. Thermal expansion will NOT create that much slop though, unless your clutch parts were made of brass or some other metal with a high thermal expansion property.