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

Water Pump Impeller Disassembly/Assembly
Water Pump Housing DisassemblyMaintenance and adjustment
The maintenance and adjustments outlined in this chapter must be carried
out in
accordance with the Periodic Maintenance Chart to keep the motorcycle in good
running condition. The initial maintenance is vitally important and must not be
neglected.
With a basic knowledge of mechanics and the ...
Air Intake Solenoid Valve Unit Test
Remove the air intake solenoid valve (see Air Intake Solenoid
Valve Removal in the Fuel System (DFI) chapter).
Set the hand tester [A] to the × 1 Ω range and connect it
to the air intake solenoid valve terminals as shown in the
figure.
Special Tool - Hand Tester: 57001-1394
...
Balancer Assemble
Apply molybdenum disulfide oil solution to the ribs of the
balancer [A].
Apply molybdenum disulfide oil solution to the ribs of the
balancer gear [A].
Check that the rubber dampers [B] are in place.
Face the linked portion [C] to the bottom.
Assemble the balancer weight ...