Clean the seat area carefully.
Coat the seat with machinist's dye.
Fit a 45° cutter [A] to the holder [B] and slide it into the
Press down lightly on the handle [C] and turn it right or
left. Grind the seating surface only until it is smooth.
Do not grind the seat too much. Overgrinding will
reduce valve clearance by sinking the valve into the
head. If the valve sinks too far into the head, it will
be impossible to adjust the clearance, and the cylin-
der head must be replaced.
Valve seat area form is as follows:
Widened Width [A] of engagement by machining with
Ground Volume [B] by 32° cutter
Correct Width [D]
Ground Volume [E] by 60° cutter
Measure the outside diameter of the seating surface with
a vernier caliper.
If the outside diameter of the seating surface is too small,
repeat the 45° grind [A] until the diameter is within the
Original Seating Surface [B]
Remove all pittings of flaws from 45° ground surface.
After grinding with 45° cutter, apply thin coat of machin-
ist's dye to seating surface. This makes seating surface
distinct and 32° and 60° grinding operation easier.
When the valve guide is replaced, be sure to grind with
45° cutter for centering and good contact.
ENGINE TOP END 4-27