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 TestFuel Tank Removal
WARNINGGasoline is extremely flammable and can be
explosive
under certain conditions, creating the
potential for serious burns. Make sure the area is
well-ventilated and free from any source of flame
or sparks; this includes any appliance with a pilot
light. Do not smoke. T ...
Special Tools
Inside Circlip Pliers:
57001-143
Oil Seal & Bearing Remover:
57001-1058
Bearing Driver Set:
57001-1129
Jack:
57001-1238
Bearing Remover Head, 15 ×
17:
57001-1267
Fork Oil Level Gauge:
57001-1290
Bearing Remover Shaft, 13:
57001-1377
Fork Oil Seal Driver, 43:
57001-15 ...
Air Cleaner Housing Assembly
Install the ducts to the air cleaner housing.
Fit the projections [A] of the duct into the slits [B] on the
air cleaner housing.
Tighten the screws [A].
Torque - Air Cleaner Housing Duct Screws: 1.1 N·m (0.11
kgf·m, 10 in·lb)
Install:
Air Cleaner Gasket [A]
Duct [B] ...