Yamaha 2008 WR450F, Owner'S Service Manual

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3-27
ELECTRICAL
ELECTRICAL
CHECKING THE SPARK PLUG
1. Remove:
• Spark plug
2. Inspect:
• Electrode "1"
Wear/damage
→
Replace.
• Insulator color "2"
Normal condition is a medium to
light tan color.
Distinctly different color
→
Check
the engine condition.
When the engine runs for many hours
at low speeds, the spark plug insula-
tor will become sooty, even if the en-
gine and carburetor are in good
operating condition.
3. Measure:
• Plug gap "a"
Use a wire gauge or thickness
gauge.
Out of specification
→
Regap.
4. Clean the plug with a spark plug
cleaner if necessary.
5. Tighten:
• Spark plug
•
Before installing a spark plug, clean
the gasket surface and plug sur-
face.
• Finger-tighten "a" the spark plug
before torquing to specification "b".
CHECKING THE IGNITION TIMING
1. Remove:
•
Timing mark accessing screw "1"
2. Attach:
•
Timing light
• Inductive tachometer
To the ignition coil lead (orange
lead"1").
3. Adjust:
•
Engine idling speed
Refer to "ADJUSTING THE EN-
GINE IDLING SPEED" section.
4. Check:
•
Ignition timing
Visually check the stationary
pointer "a" is within the firing
range "b" on the rotor.
Incorrect firing range
→
Check ro-
tor and pickup assembly.
5. Install:
• Timing mark accessing screw
CHECKING AND CHARGING THE
BATTERY
Batteries generate explosive hy-
drogen gas and contain electrolyte
which is made of poisonous and
highly caustic sulfuric acid. There-
fore, always follow these preven-
tive measures:
• Wear protective eye gear when
handling or working near batter-
ies.
•
Charge batteries in a well-venti-
lated area.
• Keep batteries away from fire,
sparks or open flames (e.g.,
welding equipment, lighted ciga-
rettes).
• DO NOT SMOKE when charging
or handling batteries.
• KEEP BATTERIES AND ELEC-
TROLYTE OUT OF REACH OF
CHILDREN.
•
Avoid bodily contact with elec-
trolyte as it can cause severe
burns or permanent eye injury.
FIRST AID IN CASE OF BODILY
CONTACT:
EXTERNAL
•
Skin — Wash with water.
• Eyes — Flush with water for 15
minutes and get immediate med-
ical attention.
INTERNAL
• Drink large quantities of water or
milk followed with milk of magne-
sia, beaten egg or vegetable oil.
Get immediate medical attention.
Charging time, charging amperage
and charging voltage for an MF
battery are different from those of
conventional batteries. The MF
battery should be charged as ex-
plained in the charging method il-
lustrations. If the battery is
overcharged, the electrolyte level
will drop considerably. Therefore,
take special care when charging
the battery.
Since MF batteries are sealed, it is
not possible to check the charge state
of the battery by measuring the spe-
cific gravity of the electrolyte. There-
fore, the charge of the battery has to
be checked by measuring the voltage
at the battery terminals.
1. Remove:
• Seat
2. Disconnect:
• Battery leads
(from the battery terminals)
First, disconnect the negative bat-
tery lead "1", and then the positive
battery lead "2".
Spark plug gap:
0.7–0.8 mm (0.028–
0.031 in)
Spark plug:
13 Nm (1.3 m•kg, 9.4
ft•lb)
Timing light:
YM-33277-A/90890-
03141