If the shaft is bent, straighten or replace it.
If the serration [B] are damaged, replace the shaft.
If the spring [C] is damaged in any way, replace it.
If the shift mechanism arm [D] is damaged in any way, replace the shaft.

If the ratchet [A], pawls [B], pins [C] or springs [D] are damaged in any way, replace them.

If it is loose, unscrew it, apply a non-permanent locking agent to the threads, and tighten it.
Torque - Shift Shaft Return Spring Pin: 29 N·m (3.0 kgf·m, 21 ft·lb)
If the lever or spring are damaged in any way, replace them.
If they are badly worn or if they show any damage, replace it.

External Shift Mechanism Installation
Wheels/TiresAdditional Considerations for High Speed Operation
Brakes: The importance of the brakes, especially during high speed
operation,
cannot be overemphasized. Check to see that they are correctly adjusted and
functioning
properly.
Steering: Looseness in the steering can cause loss of control. Check to see that
the handlebar turns freely but ha ...
Air Intake Duct Disassembly
(Other than US, CA and CAL Models)
Remove:
Air Intake Duct (see Air Intake Duct Removal)
Seal [A] and Screen [B]
Turn the air intake valve actuator [C] counterclockwise
(90°).
Remove the shaft [A] of the air intake valve actuator.
Remove:
Pad [A]
Screws [B]
Air Intake Valve [C]
...
Mode-switching
Depress the S-KTRC button on the left handlebar switch
to change the mode. The mode can be changed only when
the throttle grip is closed completely.
The S-KTRC OFF can be selected only when the motorcycle
is at a stop. Changing to mode 1 from S-KTRC OFF
is possible while riding.
NOTE
...