Chapter 2
Basic
Engine
_2._C...:J;...'l_in_d_e_r_H_e_a_d
_________________________
3,4]H3(B)(C)E
2-2 Valve seat correction procedure
The
most
common
method for correcting unevenness
of
the seat surface with a seat grinder is as follows:
(1} Use a seat grinder to make the surface even.
As the valve seat width will be enlarged, first use a 10·
grinder, then grind the seat to the standard dimension
with
a 15· grinder.
Seal grinder
Intake valve
30°
Seat grinder
Exhaust valve
45·
NOTE : When seat adjustment is necessary,
be
sure
to
check the valve and valve guide. If the clearance
exceeds the tolerance, replace the valve
or
the
valve guide,
and
then grind the seat.
Seat width
(2)
Knead
valve
compound
with oil
and
finish !he varve
seat with a lapping tool.
(3) Final finishing should
be
done
with oil only.
Lapping tool
Use a rubber
cap
type lapping
tool for cylinders without
a lapping tool groove slit.
2-6
NOTE:
Clean the valve
and
cylinder
head
with fight oil
or
the equivalent
after
valve seat finishing is com-
pleted and make sure that there are no grindings
remaining.
Lapping
tool
NO
TE:
1.
Insert adjusting shims between the valve spring
and
cylinder
head
when seats have been re-
finished
with
a seat grinder.
2.
Measure valve distortion
after
valve
seat
re-
finishing has been completed,
and
replace the
valve
and
valve seat if
it
exceeds the tolerance.
2·3
Intake/exhaust valves, valve guides
2-3.1
Wearing and corrosion
of
valve stem
Replace the valve if the valve stem is excessively worn
or
corroded.
30mm
Valve stem
outside dia.
Intake
Exhaust
60mm
Standard
,f,
7.960~
,f,
7.975
,f,
7.955~
,f,
7.970
Wear llmit
ef,7.900
¢,
7.900
Printed in
]Ilpan
HINSHI-H8009
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