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 TestClutch Cover Removal
Remove:
Right Lower Fairing (see Lower Fairing Removal in the
Frame chapter)
Clutch Cable Lower End (see Cable Removal)
Clutch Cover Bolts [A]
Turn the release lever [A] counterclockwise as shown,
and remove the clutch cover.
About 90В° [B]
...
Check 3-4: Turn Signal Indicator Light (LED) Inspection
Connect the leads in the same circuit as Check 3-2.
Connect the terminal [5] to the battery (+) terminal.
Connect the terminal [6] to the battery (+) terminal.
Check that the turn signal indicator light (LED) [A] goes
on.
If the indicator light does not go on, replace the meter ...
Battery Installation
Visually inspect the surface of the battery container.
If any signs of cracking or electrolyte leakage from the
sides of the battery.
Put the battery into the rear fender
Install the band [A].
Connect the positive (+) cable [B] (red cap) to the positive
(+) terminal first, and then ...