Replace it if necessary.

Inner Tube Inspection
Spring Tension InspectionSpark Plug Replacement
Remove the stick coils (see Stick Coil Removal in the
Electrical System chapter).
Remove the spark plugs using the 16 mm (0.63 in.) plug
wrench [A] vertically.
Replace the spark plug with new ones.
Standard Spark Plug
Type: NGK CR9EIA-9
Insert the spark plug vertically into the sp ...
Radiator and Radiator Fan Removal
Remove:
Upper Fairing Assembly (see Upper Fairing Assembly
Removal in the Frame chapter)
Coolant (Drain, see Coolant Change in the Periodic
Maintenance chapter)
Air Cleaner Housing (see Air Cleaner Housing Removal
in the Fuel System (DFI) chapter)
Coolant Reserve Tank (see Coolant R ...
Valve Seat Inspection
Remove the valve (see Valve Removal).
Check the valve seating surface [A] between the valve [B]
and valve seat [C].
Measure the outside diameter [D] of the seating pattern
on the valve seat.
If the outside diameter is too large or too small, repair the
seat (see Valve Seat Repair).
Val ...