If they appear damaged or deteriorated, replace them.

Balancer Adjustment
Torque LimiterWheel Rotation Sensor Air Gap Inspection
Raise the front/rear wheel off the ground (see Front/Rear
Wheel Removal in the Wheels/Tires chapter).
Measure the air gap between the sensor and sensor rotor
at several points by turning the wheel slowly.
Thickness Gauge [A]
Wheel Rotation Sensor Air Gap
Standard:
Front 0.4 1.6 mm ...
Clutch
Clutch Operation Inspection
Pull the clutch lever just enough to take up the free play
[A].
Measure the gap between the lever and the lever holder.
If the gap is too wide, the clutch may not release fully. If
the gap is too narrow, the clutch may not engage fully. In
either case, adjust ...
Operating Procedures
Clean the seat area carefully.
Coat the seat with machinist’s dye.
Fit a 45° cutter into the holder and slide it into the valve
guide.
Press down lightly on the handle and turn it right or left.
Grind the seating surface only until it is smooth.
NOTICE
Do not grind the seat too ...