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 InstallationAir Suction System Damage Inspection
Separate the air switching valve hose [A] from the lower
air cleaner housing [B] (see Air Cleaner Housing Removal
in the Fuel System (DFI) chapter).
Connect the following parts temporarily.
Fuel Pump Lead Connector [A]
Extension Tube [B]
Air Cleaner Housing (see Air Cleaner Hou ...
Crankcase Halves Assembly
Install:
Crankshaft (see Crankshaft Installation)
Connecting Rods (see Connecting Rod Installation)
Using a cleaning fluid, clean off any oil or dirt on the mating
surface of the crankcase halves.
Apply liquid gasket to the mating surface of the lower
crankcase half as shown in the fi ...
Diode Circuit Inspection
Remove the relay box (see Relay Box Removal).
Check conductivity of the following pairs of terminals (see
Relay Box Internal Circuit in this section).
Diode Circuit Inspection
The resistance should be low in one direction and more
than 10 times as much in the other direction. If any dio ...