6-5
Chapter 6 INSPECTION AND REPAIR OF BASIC ENGINE
1.5 Valve Face - Inspect
Inspect the valve face after the valve guide is inspected or
replaced.Lap the valve and valve seat whenever valve is
refaced or replaced.
Valve Face - Inspect
1.5.1 Valve Margin - Inspect
Measure the valve margin.If the value exceeds the limit,
reface or replace the valve with a new one.
1.5.2 Seat Width - Inspect
Apply a thin lead-free coloring paste on the valve face, and
tap the valve face against valve seat with valve lapper to
check the contact condition.If the contact is not even, or any
defects are found, or if the value exceeds the specified limit,
reface or replace the valve or valve seat.
Note: Do not rotate the valve when pressing valve face coat-
ed with lead-free coloring paste against valve seat.
Seat Width - Inspect
Contact condition between valve seat and valve
1.6 Valve Face - Reface
When the valve is re-used by refacing, use valve refacer.
Note:(a) Grind the valve face with valve refacer adjusted to
the specified angle.
(b) The valve margin is to be within the specified lim-
it.If the dimensions after refacing does not meet the
specified values, replace the valve with a new one.
Valve Face - Reface
Valve margin
Valve sinkage
Seat width
Valve seat angle
Item Standard value Limit value
Va lv e
seat
Valve seat angle 30° -
Seat
width
Inlet
1.98 to 2.18 mm
[0.0780 to 0.0858 in.]
2.5 mm
[0.098 in.]
Exhaust
1.75 to 1.95 mm
[0.0689 to 0.0768 in.]
2.3 mm
[0.09 in.]
Valve margin
Inlet
2.7 to 3.1 mm
[0.1063 to 0.1220 in.]
2.0 mm
[0.078 in.]
Exhaust
2.8 to 3.2 mm
[0.1102 to 0.1260 in.]
Valve lapper
P/N:30091-08800
Lapping
compound
Good
Bad
Grind valve face
at specified angles.
Valve refacer
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