Electrical; Spark Plug; Battery - Yamaha LB50IIAC Service Manual

ELECTRICAL
Spark plug
The spark plug indicates how the engine is
operating. If the engine is operating correct-
ly, and the machine is being ridden correctly,
then the tip of the white insulator around the
positive electrode of the spark plug will be a
medium tan color. If the insulator is very
dark brown or black color, then a plug with a
hotter heat range might be required. This
situation is quite common during the engine
break-in period.
If the insulator tip shows a very light tan or
white color is actually pure white and glazed
or if electrodes show signs of melting, then
a spark plug with a colder heat range is re-
quired.
Remember, the insulator area surrounding
the positive electrode of the spark plug must
be a medium tan color. If it is not, check car-
buretion, timing and ignition adjustments.
The spark plug must be removed and check-
ed. Check electrode wear, insulator color,
and electrode gap.
Battery
A poorly maintained battery will deteriorate
quickly.
The battery fluid should be checked at least
once a month.
1. The level should be between the upper
and lower level marks. Use only distill-
ed water if refilling is necessary.
NOTE:~~~~~~~~~~­
Normal tap water contains minerals
which are harmful to a battery;
therefore, refill only with distilled water.
2. Always make sure the connections are
correct when putting the battery back in
the motorcycle. The red lead is for the
+
terminal and the black lead is for the
- terminal. Make sure the breather
pipe is properly conhected and is not
damaged or obstructed.
-46-
Spark plug gap:
0.5 - 0.6 mm
Engine heat and combustion chamber
deposits will cause any spark plug to slowly
break down and erode. If the electrodes
finally become too worn, or if for any reason
you believe the spark plug is not functioning
correctly, replace it
When installing the plug, always clean the
gasket surface, use a new gasket, wipe off
any grime that might be present on the sur-
face of the spark plug, torque the spark plug
properly.
Standard Spark Plug
Tightening Torque
NGK
B-6HS
2 .5 - 3.0 m • kg