Replace it if necessary.

Inner Tube Inspection
Spring Tension InspectionRear Frame Front Removal
Remove:
Rear Frame Rear (see Rear Frame Rear Removal)
Rear Fender Front (see Rear Fender Front Removal)
Rear Footpeg Bracket Bolts [A]
Rear Footpeg Bracket [B]
Rear Frame Front Bolts [C]
Left Rear Frame Front [D]
Remove:
Rear Footpeg Bracket Bolts [A]
Rear Footpeg Bracke ...
Brake Disc Warp Inspection
Raise the wheel off the ground with the jack.
Special Tools - Jack: 57001-1238
Jack Attachment: 57001-1608
For front disc inspection, turn the handlebar fully to one
side.
Set up a dial gauge against the disc [A] as shown in
the figure and measure disc runout, while turning [B] the
...
Drive Chain Wear Inspection
Remove the chain cover (see Drive Chain Removal/Installation
in the Final Drive chapter).
Rotate the rear wheel to inspect the drive chain for damaged
rollers, and loose pins and links
If there is any irregularity, replace the drive chain.
Lubricate the drive chain if it appears dry.
...