Replace it if necessary.

Inner Tube Inspection
Spring Tension InspectionAir 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]
...
Engine Sprocket Installation
Replace the sprocket washer and axle cotter pin.
Install the engine sprocket onto the output shaft.
Apply molybdenum disulfide oil solution to the threads
and seating surface of the engine sprocket nut.
Tighten:
Torque - Engine Sprocket Nut: 145 N·m (14.8 kgf·m, 107
ft·lb)
NOTE
...
Inner Tube Inspection
Visually inspect the inner tube [A].
If there is any damage, replace the inner tube. Since
damage to the inner tube damages the oil seal, replace
the oil seal whenever the inner tube is replaced.
NOTICE
If the inner tube is badly bent or creased, replace
it. Excessive bending, followed by ...