Suzuki SY413 Service Manual page 1759

INSPECT BRAKE DISC
Before this inspection, brake pads must be removed (according to
step 1) to 8) of "REMOVAL" under "REMOVE AND INSTALL PAD
(SHOE & LINING)" of "REAR DISC BRAKE" in this section.
Check disc surface for scratches in wearing parts.
Scratches on disc surface noticed at the time of specified inspec-
tion or replacement are normal and disc is not defective unless they
are serious.
But when there are deep scratches or scratches all over disc sur-
face, replace it. When only one side is scratched, polish and correct
that side.
Disc thickness
Standard :10 mm (0.39 in.)
Limit : 8 mm (0.31 in.)
To measure deflection of disc, take measurement at 2 points on its
periphery and center with dial gauge while rotating it.
Limit on disc deflection: 0.1 mm (0.0039 in.)
NOTE:
Check front wheel bearing for looseness before measure-
ment.
BRAKES 5-65