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

Water Pump Impeller Disassembly/Assembly
Water Pump Housing DisassemblyUpper Crankcase Assembly
When installing the breather plate, replace the gasket [A]
with a new one.
Apply a non-permanent locking agent to the threads of
the bolts [A] and tighten them.
Torque - Breather Plate Bolts: 9.8 N·m (1.0 kgf·m, 87 in·lb)
Install the fitting [A] until it is bottomed ...
Main Throttle Sensor Resistance Inspection
Turn the ignition switch to OFF.
Measure the main throttle sensor resistance in the same
way as input voltage inspection, note the following.
Disconnect the throttle sensor setting adapter [A] from the
connector of the main harness side.
Special Tool - Throttle Sensor Setting Adapter: 57 ...
Key Registration
Case 1: When the ignition key has been lost or additional
spare ignition key is required.
Prepare a new spare ignition key.
Cut the key in accordance with the shape of the current
ignition key.
Remove the rear seat (see Rear Seat Removal in the
Frame chapter).
Remove the immobilizer/K ...