If the disc has worn past the service limit, replace it.
Measuring Area [B]
Brake Disc Thickness Standard:
Front 5.3 
5.7 mm (0.21
0.22 in.)
Rear 4.8 
5.2 mm (0.19
0.20 in.)
Service Limit:
Front 5.0 mm (0.20 in.)
Rear 4.5 mm (0.18 in.)
Brake Disc Installation
Brake Disc Warp InspectionCylinder (Upper Crankcase) Wear Inspection
Split the crankcase (see Crankcase Splitting).
Remove the pistons (see Piston Removal).
Assemble the cylinder (upper crankcase) [A], the cylinder
head [B] and the cylinder head gasket [C].
Tighten the cylinder head bolts (see Cylinder Head Installation
in the Engine Top End chapter).
...
Release Shaft Installation
Apply grease to the oil seal lips on the upper ridge of the
clutch cover.
Apply engine oil to the needle bearings in the hole of the
clutch cover.
Applymolybdenum disulfide grease to the pusher-holding
portion [A] on the release shaft.
Install the washer [B] and spring [C].
...
Warning Indicator Light (Red)
This red warning indicator light and
the oil pressure warning symbol ( )
should go on whenever the ignition
switch is turned to “ON” and go off after
starting the engine.
A. Warning Indicator Light (Red)
B. Warning Symbols
This red warning indicator light has
the two warning function ...