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 TestSpecial Tools and Sealant
Compression Gauge, 20 kgf/cm²:
57001-221
Valve Spring Compressor Assembly:
57001-241
Valve Spring Compressor Adapter,
25:
57001-1019
Valve Seat Cutter, 45° - 27.5:
57001-1114
Valve Seat Cutter, 45° - 32:
57001-1115
Valve Seat Cutter, 32° - 28:
57001-1119
Valve Seat Cutter ...
Torque Limiter Removal
Remove:
Starter Motor (see Starter Motor Removal in the Electrical
System chapter)
Throttle Body Assy Holder [A]
Breather Hose [B]
Roll up the heat insulation rubber plate [C].
Remove:
Torque Limiter Cover Bolts [A]
Torque Limiter Cover [B]
Remove:
Torque Limit ...
Swingarm Bearing, Sleeve Inspection
NOTICE
Do not remove the bearings for inspection. Removal
may damage them.
Inspect the needle bearings [A] and ball bearing installed
in the swingarm.
The rollers and ball in a bearing normally wear very little,
and wear is difficult to measure. Instead of measuring,
visually inspec ...