There's a manual in the download section on this site.
Full description of the clutch and all its parts starts at page 143 on the download. It's section 4-31 in the manual. definitely worth you time looking at it.
The Yamaha manual I have for the FZS600 1998 shows:-
Clutch friction plate thickness 2.94 - 3.06 mm Limit 2.8 mm
Clutch spring free length 34.9 mm Limit 34.3 mm
Full description of the clutch and all its parts starts at page 143 on the download. It's section 4-31 in the manual. definitely worth you time looking at it.
The Yamaha manual I have for the FZS600 1998 shows:-
Clutch friction plate thickness 2.94 - 3.06 mm Limit 2.8 mm
Clutch spring free length 34.9 mm Limit 34.3 mm