Measure the outside diameter [D] of the seating pattern on the valve seat.
If the outside diameter is too large or too small, repair the seat (see Valve Seat Repair).
Valve Seating Surface Outside Diameter Standard:
Exhaust 23.9 
24.1 mm (0.941
0.949 in.)
Intake 30.4 
30.6 mm (1.197
1.205 in.)
Measure the seat width [E] of the portion where there is no build-up carbon (white portion) of the valve seat with a vernier caliper.
Good [F]
If the width is too wide [G], too narrow [H] or uneven [J], repair the seat (see Valve Seat Repair).
Valve Seating Surface Width Standard:
Exhaust 0.8 
1.2 mm (0.03
0.05 in.)
Intake 0.5 
1.0 mm (0.02
0.04 in.)
Valve-to-Guide Clearance Measurement (Wobble Method)
Valve Seat RepairAir Switching Valve Removal
NOTICE
Never drop the air switching valve especially on a
hard surface. Such a shock to the air switching
valve can damaged it.
Remove the air cleaner housing (see Air Cleaner Housing
Removal in the Fuel System (DFI) chapter).
Disconnect the connector [A].
Disconnect the hoses [B] from ...
Sprocket Wear Inspection
Visually inspect the engine and rear sprocket teeth for
wear and damage.
If the teeth are worn as illustrated, replace the sprocket,
and inspect the drive chain wear (see Drive Chain Wear
Inspection in the Periodic Maintenance chapter).
Worn Tooth (Engine Sprocket) [A]
Worn Tooth (Rear ...
Air Switching Valve
Air Switching Valve Operation Test
Refer to the Air Suction System Damage Inspection in the
Periodic Maintenance chapter.
Air Switching Valve Unit Test
Remove the air switching valve (see Air Switching Valve
Removal in the Engine Top End chapter).
Set the hand tester [A] to the × 1 ...