Honda WB20XT2, Manual

Page: 109 / 132

12-10
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CYLINDER HEAD WB20XT2•WB30XT2
Check the valve guide bore; it should be straight, round,
and centered in the valve guide. Insert the valve and
check operation. If the valve does not operate
smoothly, the guide may have been bent during
installation.
Replace the valve guide if it is bent or damaged (page
12-8).
Check the valve guide-to-stem clearance (page 12-7).
VALVE SEAT RECONDITIONING
Inspect the valve seat contact area (page 12-6).
Using a 45° seat cutter, remove any roughness or
irregularities from the seat.
If the contact area is too low on the valve, the seat must
be raised using a 60° interior cutter.
If the contact area is too high on the valve, the seat
must be lowered using a 31° flat cutter.
Valve seat cutter (1), grinder or equivalent valve seat
refacing equipment is recommended to correct a worn
valve seat.
• Turn the cutter clockwise, never counterclockwise.
• Continue to turn the cutter as you lift it from the valve
seat.
Make a light pass with the 45° cutter to remove any
possible burrs at the edge of the seat.
Be sure that the width of the finished valve seat is within
specification.
45°
60°
31°
TOO LOW
TOO HIGH
TOOLS (Commercially available):
Valve seat cutter, 31°
NWYCU115
Valve seat cutter, 45° NWYCU122
Valve seat cutter, 60° MWYCU111
Solid pilot (short) 5.5 mm NWYPM10055SH
Accessory kit NWYKACC246
T-wrench NWYTW505
Adapter, 1/2"-3/8" NWYTW503-1
(1)
STANDARD:
WB20XT2:
IN/EX: 0.70 – 0.90 mm (0.028 – 0.035 in)
WB30XT2:
IN: 0.70 – 0.90 mm (0.028 – 0.035 in)
EX: 0.90 – 1.10 mm (0.035 – 0.043 in)
45°