5. Inspection and Servicing of Basic Engine Parts
103
5.2.7 Intake and exhaust rocker arms
The wear of rocker arm and rocker arm bushing may
change opening/closing timing of the valve, and may in
turn affect the engine performance according to the
extent of the change.
(1) Rocker arm shaft and rocker arm bushing
Measure the outer diameter of the shaft and the inner-
diameter of the veering, and replace if wear exceeds
the limit.
Replace the rocker arm bushing if it moves and replace the entire rocker arm if there is no tightening
clearance.
(2) Rocker arm spring
Check the rocker arm spring and replace it if it is corroded or worn.
(3) Rocker arm and valve cap wear
(4) Inspect the contact surface of the rocker arm and replace it if there is abnormal wear or
flaking.
5.2.8 Adjustment of valve clearance
(1) Make adjustments when the engine is cool.
(Refer to 2.2.2(5).)
(2) Be sure that the opening and closing angles
for both the intake and the exhaust valves
are checked when the timing gear is
disassembled (The gauge on the flywheel
can be read.).
mm
Standard
Limit
Outside dia of intake and
exhaust rocker arm shaft.
15.966-15.984
15.955
Intake and exhaust rocker
arm bushing inside dia.
16.000-16.020
16.090
Rocker arm shaft and
bushing clearance at
assembly
0.016-0.054
0.140
mm
Intake and exhaust valve clearance
0.15-0.25
deg.
Intake valve Open
b.TDC.
10°-20°
Intake valve Closed
a.BDC.
40°-50°
Exhaust valve Open
b.BDC.
51°-61°
Exhaust valve Closed
a.TDC.
13°-23°
(Rocker arm hole diameter)
T.D.C.
Exhaust 254
Intake 281
13
23
10
20
51
61
40
50
B.D.C.
