Repair Operating Procedures
Clean the seat area carefully.
Coat the seat with machinist's dye.
Fit a 45° cutter into the holder and slide it into the valve
Press down lightly on the handle 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.
Widened Width [A] of engagement by machining with
Ground Volume [B] by 32° cutter
Correct Width [D]
Ground Volume [E] by 55° 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° [A] grind 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 55° grinding operation easier.
When the valve guide is replaced, be sure to grind with
45° cutter for centering and good contact.
If the outside diameter [A] of the seating surface is too
large, make the 32° [B] grind described below.
If the outside diameter of the seating surface is within the
specified range, measure the seat width as described be-
Grind the seat at a 32° angle until the seat outside diam-
eter is within the specified range.
To make the 32° grind, fit a 32° cutter into the holder, and
slide it into the valve guide.
Turn the holder one turn at a time while pressing down
very lightly. Check the seat after each turn.
ENGINE TOP END 5-31