Yamaha F50A - Checking the Spark Plugs

CHK
ADJ
Periodic checks and adjustments
3-11
62Y3A11
5. Turn the flywheel clockwise and align the
“4” mark
c
on the driven sprocket with
the “” mark
b
on the cylinder head.
CAUTION:
Do not turn the flywheel counterclock-
wise, otherwise the valve system may be
damaged.
6. Check the intake valve clearance for cyl-
inders #3 and #4, and the exhaust valve
clearance for cylinders #2 and #4. Adjust
if out of specification.
NOTE:
Adjust the valve clearance when the engine
is cold.
7. Loosen the locknut
4
, and then turn the
adjusting screw
5
until the specified
valve clearance is obtained.
NOTE:
• To decrease the valve clearance, turn the
adjusting screw clockwise.
• To increase the valve clearance, turn the
adjusting screw counterclockwise.
8. Tighten the locknut, and then check the
valve clearances. Adjust if necessary.
9. Install the cylinder head cover, fuel
pump, and spark plugs.
10. Connect the blowby hose and high-ten-
sion cords, and then install the flywheel
magnet cover.
Checking the spark plugs
1. Disconnect the high-tension cords, and
then remove the spark plugs.
Valve clearance:
Intake
d
:
0.20
±
0.05 mm (0.008
±
0.002 in)
Exhaust
e
:
0.30
±
0.05 mm (0.012
±
0.002 in)