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 TestBrake Disc Warp Inspection
Raise the wheel off the ground with the jack.
Special Tools - Jack: 57001-1238
Jack Attachment: 57001-1608
For front disc inspection, turn the handlebar fully to one
side.
Set up a dial gauge against the disc [A] as shown in
the figure and measure disc runout, while turning [B] the
...
Intake Air Pressure Sensor #1 Output Voltage Inspection
Measure the output voltage at the intake air pressure sensor
#1 in the same way as input voltage inspection, note
the following.
Disconnect the intake air pressure sensor #1 connector
and connect the measuring adapter [A] between these
connectors.
[B] Main Harness
[C] Intake Air Pressu ...
Brake Hose and Pipe Replacement
NOTICE
Brake fluid quickly ruins painted plastic surfaces;
any spilled fluid should be completely washed away
immediately.
Remove:
Upper Fairing Assembly (see Upper Fairing Assembly
Removal in the Frame chapter)
Brake Hose Fitting Bolt [A]
Brake Hose Banjo Bolts [B]
Bolt [C]
Clamp ...