Service Manual

5-38 ENGINE TOP END
Cylinder Head
Seat Cutter Operation Care:
1. This valve seat cutter is developed to grind the valve for
repair. Therefore the cutter m ust not be used for other
purposes than seat repair.
Do not drop or shock the valve seat cutter, or the diamond
particles may fall off.
Do not fail to apply engine oil to the valve seat cutter be-
fore grinding the seat surface. Also wash off ground parti-
cles sticking to the cutter with washing oil.
CAUTION
Do not use a wire brush to remove the metal par-
ticles from the cutter. It will take off the diamond
particles.
Setting the valve seat cutter holder in position, operate
the cutter in one hand. Do not apply too much force to the
diamond portion.
NOTE
○
Prior to grinding, apply engine oil to the cutter. During
operation, wash off any ground particles sticking to the
cutter with washing oil
After use, wash it with washing oil and apply thin layer of
engine oil before storing.
Operating Procedures:
•
Clean the seat area carefully.
•
Coat the seat with machinist’s dye.
•
Fit a 45° cutter [A] i nto the holder [B] and slide it into the
valve guide.
•
Press down lightly on the handle and turn it right or left
[C]. Grind the seat surface only until it is smooth.
CAUTION
Do not grind the seat too much. O vergrinding will
reduce valve clearance by sinking the valve into the
head. If the valve sinks too far into the head, HLA
could not work and the cylinder head must be re-
placed.
•
Measure the outside diameter [A] of the seat surface (seat
O.D.) with vernier calipers.
If the seat O.D. is too small, repeat the 45° grind [B] until
the diameter is within the specified range.
Ground Voluum [C]
NOTE
○
Remove all pittings or flaws from 45° ground surface.
○
After grinding with 45° cutter, apply thin coat of machin-
ist’s dye to seat surface. This makes seat surface dis-
tinct 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 seat O.D. is too large, make the 32° grind described
below.