Service manual

ENGINE INSPECTION
'/:,.,- .. _ SEAT INSERT
d. Check for contact between the valve and valve seat
by applying a thin coat of Prussian Blue (or Redlead)
on the valve seat contact face, then insert the valve into
the valve guide and press
fit the valve on the valve seat.
NOTE: Do not rotate the valve!
CONTACT FACE
INTAKE
~~
CONTACT FACE I
...... ··4.5~"'if' ::,.:)""",.\"." ..
e. Check if the valve seat contact face contacts the center
position
of the valve contact face. If the contact posi-
tion
is not centered, recut and surface the valve seat
and valve.
4. Stem Wear Inspection. If the valve stem is bent or its
diameter is less than the limit, replace the valve.
Stem diameter limit Intake 0.351 in (8.904 mm)
Exhaust 0.350 in (8.884 mm)
J:HECKING VALVE STEM WEAR
VALVE SEAT
1. Valve Seat Angle. Valve seat angle is 45° and 30°
respectively for intake and exhaust sides. The standard
contact width
of the valve seat is 0.079 in (2.0 mm) for
both intake and exhaust sides.
If the valve margin is less
than the permissible limit, replace the valve.
2. Refacing
the Valve and Valve Seat. Reface in the fol-
lowing order:
a. Reface the valve with a valve grinder to the specified
angle.
h. Reface the valve seat with a valve seat cutter while
checking the contact between the valve and the valve
seat.
NOTE: Reface the valve seat taking care that the valve
seat contacts the center position
of the valve.
45· Intake, 30· Exhaust
Valve Seat Angle
Valve Seat Width 0.079in (2.0mm) Intake and Exhaust
1.25 in (31.7 mm)
EXHAUST
c. Reface the valve and valve seat with a valve tapping
compound.
d. Remeasure dimension
"L".
e. Adjust dimension "L" to the standard by adding some
washers between the lower spring seat and cylinder
head.
Engines & Generators
16