144
POWERHEAD
CYLINDER HEAD
Drive valve guide in from valve spring side to the
specified height.
Measure valve guide protrusion:
•
Protrusion: 0.39 ± 0.02 in (10.0 ± 0.5 mm)
Ream valve guide bore with 5.5 mm reamer.
Clean and oil the valve guide bore after reaming.
Valve Seat Servicing
If the contact between valve and seat is not uni-
form, the valve seat must be refaced.
Both intake and exhaust valve seats have three
chamfer angles:
•
IN: 30°, 45°, 60°
•
EX: 30°, 45°, 75°
Use 45° cutter to reface valve seat.
IMPORTANT:
Turn cutter clockwise, never
counterclockwise.
Measure valve seat contact width. Refer to
If width is too high (wide), reface valve seat using
30° cutter.
If width is to low (narrow), reface valve seat using
60° cutter (intake) or 75° cutter (exhaust).
IMPORTANT:
Grind seat areas minimally only.
Do not grind more than necessary.
1.
Valve guide protrusion
005685
005686
005687
1.
Too high (wide)
2.
Too low (narrow)
004539
