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

Water Pump Impeller Disassembly/Assembly
Water Pump Housing DisassemblyCrankshaft Sensor Removal
Remove:
Fuel Tank (see Fuel Tank Removal in the Fuel System
(DFI) chapter)
Crankshaft Sensor Lead Connector [A]
Remove:
Right Lower Fairing (see Lower Fairing Removal in the
Frame chapter)
Bolts [A]
Crankshaft Sensor Cover [B] and Gasket
Oil Pressure Switch Terminal [C]
...
Special Tools
Bearing Driver Set:
57001-1129
Jack:
57001-1238
Bearing Remover Head, 25 × 28:
57001-1346
Bearing Remover Shaft, 13:
57001-1377
Jack Attachment:
57001-1608 ...
Charging Condition Inspection
Battery charging condition can be checked by measuring
battery terminal voltage with a digital voltmeter [A].
Remove the seat (see Seat Removal in the Frame chapter).
Disconnect the battery terminals.
NOTICE
Be sure to disconnect the negative (–) cable first.
Measure the battery ...