Valve Seat

1. Apply a thin coat of prussian blue (or white lead) to the valve face.
2. Lightly press the valve against the seat, do not rotate the valve.
3. Check the valve face and seat for the following:
(a) If blue appears 360° around the face, the valve is concentric. If not, replace the valve.
(b) If blue appears 360° around the valve seat, the guide and face are concentric. If not, resurface the seat.
4. Check that the seat contact is in the middle of the valve face with the following width:
Intake: 1.0-1.4 mm (0.039-0.055 inch).
Exhaust: 1.2-1.6 mm (0.047-0.063 inch).