Yamaha F4A - Checking the Spark Timing

POWER UNIT
INSP
ADJ
E
3-8
8. Install:
9Gasket (cylinder head cover)
9Cylinder head cover
9. Install:
9Spark plug
c
d
7
7
6
1
2
3
7. Tighten:
9locknut 6
NOTE:
Tighten the locknut, keeping the adjuster
fixed.
Locknut (rocker arm):
10 Nm (1.0 m•kg, 7.2 ft•lb)
Cylinder head cover:
11 Nm (1.1 m•kg, 8.0 ft•lb)
Checking the spark timing
NOTE:
Spark timing is controlled automatically by
the ignitor ass’y. For this reason only the
checking procedure is shown in this sec-
tion.
1. Set:
9Tachometer
9Timing light
To spark plug lead for cylinder.
Tachometer:
YU-08036-A/90890-06760
Timing light:
YU-33277-A/90890-03141
Adjustment steps:
8 Loosen the lock nut and insert the
0.10 mm (0.004 in) feeler gauge be-
tween rocker arm and valve stem.
8 Turn adjuster 7 to obtain the proper
clearance.
Turning in
cc
® Valve clearance decreases.
Turning out
dd
® Valve clearance increases.
6. Adjust:
9Intake valve clearance
9Exhaust valve clearance