Valve Seat Inspection
Remove the valve (see Valve Removal).
Check the valve seat surface [A] between the valve [B]
and valve seat [C].
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 Seat Surface Outside Diameter
Exhaust 19.9 ∼ 20.1 mm (0.783 ∼ 0.791 in.)
22.9 ∼ 23.1 mm (0.902 ∼ 0.909 in.)
The valve stem and guide must be in good condition or
this check will not be valid.
If the valve seating pattern is not correct, repair the seat.
Check the seating surface width of the valve seat.
Measure the seat width [E] of the portion where there is
no build-up carbon (white portion) of the valve seat with a
If the width is too wide [G], too narrow [H] or uneven [J],
repair the seat (see Valve Seat Repair).
Valve Seat Width
Exhaust 0.80 ∼ 1.15 mm (0.031 ∼ 0.045 in.)
0.80 ∼ 1.15 mm (0.031 ∼ 0.045 in.)
ENGINE TOP END 4-25