NOTICE
Never drop the air switching valve especially on a hard surface. Such a shock to the air switching valve can damaged it.

Air Suction Valve Inspection
Air Switching Valve InstallationThrottle Body Assy Holder Installation
Be sure to install the new O-rings [A].
Using a high flash-point solvent, clean off any oil or dirt
that may be on the silicone sealant coating area. Dry
them with a clean cloth.
Apply silicone sealant to any two positions of the new O
-ring.
Sealant - Liquid Gasket, TB1211F: 92104-0 ...
Valve Removal
Remove the cylinder head (see Cylinder Head Removal).
Remove the valve lifter and shim.
Mark and record the valve lifter and shim locations so they
can be installed in their original positions.
Using the valve spring compressor assembly, remove the
valve.
Special Tools - Valve ...
Valve Guide Removal
Remove:
Valve (see Valve Removal)
Oil Seal
Spring Seat
Heat the area around the valve guide to 120
150°C (248
302°F), and hammer lightly on
the valve guide arbor [A]
to remove the guide from the top of the head.
NOTICE
Do not heat the cylinder head with a torch. This ...