Replace it if necessary.

Inner Tube Inspection
Spring Tension InspectionCheck 2-1: Speedometer Inspection
Using the suitable stand, raise the rear wheel off the
ground.
Rotate the rear wheel by hand or start the engine.
Check that the display changes speedometer.
If the display function does not work, check the following
parts.
Rear Wheel Rotation Sensor (see Wheel Rotation Sensor
Inspe ...
Camshaft, Camshaft Cap Wear Inspection
Remove the camshaft caps (see Camshaft Removal).
Cut the strips of plastigage (press gauge) to journal width.
Place a strip on each journal parallel to the camshaft installed
in the correct position.
Tighten the camshaft cap bolts and upper camshaft chain
guide bolts to the specified ...
Special Tools and Sealant
Compression Gauge, 20 kgf/cm²:
57001-221
Valve Spring Compressor Assembly:
57001-241
Valve Spring Compressor Adapter,
25:
57001-1019
Valve Seat Cutter, 45° - 27.5:
57001-1114
Valve Seat Cutter, 45° - 32:
57001-1115
Valve Seat Cutter, 32° - 28:
57001-1119
Valve Seat Cutter ...