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

Water Pump Impeller Disassembly/Assembly
Water Pump Housing DisassemblySteering Play Adjustment
Remove:
Steering Stem Head with Handlebars (see Handlebar
Removal in the Steering chapter).
Bend the claws [A] of the claw washer [B] straighten.
Remove:
Steering Stem Locknut [C]
Claw Washer
Adjust the steering using the steering stem nut wrench
[A].
Special Tool - Ste ...
Mud Guard Installation
Installation is the reverse of removal. Note the following.
Run the hose and lead correctly (see Cable, Wire, and
Hose Routing section in the Appendix chapter).
Check the brake line.
Apply a non-permanent locking agent to the threads of
the mud guard mounting bolts [A, B], and tighten them ...
Oil Level Inspection
Check that the engine oil level is between the upper [A]
and lower [B] levels in the gauge.
NOTE
Situate the motorcycle so that it is perpendicular to the
ground.
If the motorcycle has just been used, wait several minutes
for all the oil to drain down.
If the oil has just been changed, ...