Replace it if necessary.

Inner Tube Inspection
Spring Tension InspectionValve Removal
Remove the cylinder head (see Cylinder Head Removal).
Remove the valve lifter and shim.
Mark and record the valve lifter and shim locations so they
can be installed in their original positions.
Using the valve spring compressor assembly, remove the
valve.
Special Tools - Valve ...
ESD (Electronic Steering Damper) ECU Removal (ZX1000JD/KD)
NOTICE
Never drop the ECU especially on a hard surface.
Such a shock to the ECU can damage it.
Lift up the front portion of the fuel tank, and hold it with a
suitable bar or block (see Fuel Tank Removal in the Fuel
System (DFI) chapter).
NOTE
When removing the ESD ECU only, there ...
Coolant Reserve Tank Installation
Install the following to the coolant reserve tank [A].
Pad [B]
Gasket [C]
Cap [D]
Collar [E]
Install the coolant reserve tank and tighten the bolt [F].
Run the hoses correctly (see Cable,Wire, and Hose Routing
section in the Appendix chapter).
Fill the coolant reserve tank with ...