When the engine is running, the air intake valve is lifting up.
If the valve does not operate properly, check the air intake solenoid valve hoses for leak.
If there are no leaks, check the air intake solenoid valve.

Air Intake Solenoid Valve Unit TestGear Position Switch Output Voltage Inspection
NOTE
Be sure the battery is fully charged.
Turn the ignition switch to OFF.
Remove the fuel tank (see Fuel Tank Removal in the Fuel
System (DFI) chapter).
Disconnect the sidestand switch/gear position switch lead
connector [A].
Connect the measuring adapter [A] between the ...
Engine Stop Switch Operation Inspection
First Step
Set the gear position in the neutral position.
Turn the ignition switch to ON.
Turn the engine stop switch to stop position [A].
Push the starter button.
The engine does not start.
If the engine starts, inspect the engine stop switch (see
Switch Inspection in the Electri ...
Oil Pump Removal
Remove:
Coolant (Drain, see Coolant Change in the Periodic
Maintenance chapter)
Engine Oil (Drain, see Engine Oil Change in the Periodic
Maintenance chapter)
Sidestand Switch Lead Connector [A] (Disconnect)
Bolt [B] and Water Pipe [C]
Water Pump Cover Bolts [D]
Water Pump Cover [E ...