Operating Procedures

CAUTION

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 cylin­der head must be replaced.

• Clean the seat area carefully.

• Coat the seat with machinist’s dye.

• Fit a 45° cutter to the holder and slide it into the valve guide.

• Press down lightly on the handle and turn it right or left. Grind the seating surface only until it is smooth.

[A] Grind the seat at a 45° angle to enlarge the width of the seating surface.

[B] 32° cut

[C] 32°

[D] Specified seating surface width

[E] 60° cut

[F] 60°

ENGINE TOP END 5-29

Valves

• Measure the outside diameter (O.D.) 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 specified range.

Original Seating Surface [B]

NOTE

ORemove all pittings of flaws from 45° ground surface.

О After grinding with 45° cutter, apply thin coat of machin­ist’s dye to seating surface. This makes seating surface distinct and 32° and 60° grinding operation easier.

О When the valve guide is replaced, be sure to grind with 45° cutter for centering and good contact.

• If the outside diameter of the seating surface is too large, make the 32° grind described below.

• If the outside diameter [A] of the seating surface is within the specified range, measure the seat width as described below.

• Grind the seat at a 32° angle [B] until the seat O.D. is within the specified range.

OTo make the 32° grind, fit a 32° cutter to the holder, and

slide it into the valve guide. OTurn the holder one turn at a time while pressing down

very lightly. Check the seat after each turn.