If the surface is corroded or if the blades are damaged, replace the impeller

Water Pump Impeller Disassembly/Assembly
Water Pump Housing DisassemblySafe riding technique
The points given below are applicable for everyday motorcycle use and
should
be carefully observed for safe and effective vehicle operation.
For safety, eye protection and a
helmet are strongly recommended.
You should be aware of and verify
the applicable safety regulations in
force prior ...
Subthrottle Valve Actuator Input Voltage Inspection
NOTE
Be sure the battery is fully charged.
Turn the ignition switch to OFF.
Disconnect the subthrottle valve actuator connector and
connect the measuring adapter [A] between these connectors
as shown in the figure.
Main Harness [B]
Subthrottle Valve Actuator [C]
Special Tool ...
Front Fork Inspection
Holding the brake lever, pump the
front fork up and down several times
to inspect smooth stroke.
Visually inspect the front fork for oil
leakage, scoring or scratches on the
outer surface of the inner tube.
If any doubt about the front fork, it
should be checked by an authorized
K ...