Yamaha Wr 450 F Owners Manual

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STEERING HEAD INSPECTION AND ADJUSTMENT
Tighten the ring nut 3 using ring nut
wrench 4.
NOTE:
Set the torque wrench to the ring nut wrench
so that they form a right angle.
Ring nut wrench:
YU-33975/90890-01403
T R..
Ring nut (initial tightening):
38 Nm (3.8 m • kg, 27 ft • lb)
Loosen the ring nut one turn.
Retighten the ring nut using the ring nut
wrench.
WARNING
Avoid over-tightening.
T R..
Ring nut (final tightening):
7 Nm (0.7 m • kg, 5.1 ft • lb)
Check the steering shaft by...

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LUBRICATION
LUBRICATION
To ensure smooth operation of all compo-
nents, lubricate your machine during setup,
after break-in, and after every race.
1All control cable
2Clutch lever pivot
3Shift pedal pivot
4Footrest pivot
5Throttle-to-handlebar contact
6Drive chain
7Tube guide cable winding portion
8Throttle cable end
9Clutch cable end
0Hot starter cable endÅUse Yamaha cable lube or equivalent on these
areas.
ıUse SAE 10W-30 motor oil or suitable chain
lubricants.
ÇLubricate the following...

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ELECTRICAL/SPARK PLUG INSPECTION
EC370000
ELECTRICAL
EC371001
SPARK PLUG INSPECTION
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.
NOTE:
When the engine runs for many hours at low
speeds, the spark plug insulator will become
sooty, even if the engine and carburetor are in
good operating condition.
3. Measure:
Plug gap a 
Use a wire gauge...

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IGNITION TIMING CHECK
IGNITION TIMING CHECK
1. Remove:
Timing plug 1 
1
2. Attach:
Timing light 
Inductive tachometer 
To the ignition coil lead (orange lead
1).
3. Check:
Ignition timing
Timing light:
YM-33277-A/90890-03141
Inductive tachometer:
YU-8036-B
Engine tachometer:
90890-03113
Checking steps:
Start the engine and let it warm up. Let the
engine run at the specified speed.
Adjust the engine idling speed.
Refer to “IDLE SPEED ADJUSTMENT”
section.
Visually check the...

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BATTERY INSPECTION AND CHARGING
WARNING
Batteries generate explosive hydrogen gas
and contain electrolyte which is made of
poisonous and highly caustic sulfuric acid. 
Therefore, always follow these preventive
measures: 
Wear protective eye gear when handling
or working near batteries. 
Charge batteries in a well-ventilated area. 
Keep batteries away from fire, sparks or
open flames (e.g., welding equipment,
lighted cigarettes). 
DO NOT SMOKE when charging or han-
dling batteries....

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BATTERY INSPECTION AND CHARGING
NOTE:
Since MF batteries are sealed, it is not possi-
ble to check the charge state of the battery by
measuring the specific gravity of the electro-
lyte. Therefore, 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)
CAUTION:
First, disconnect the negative battery lead
1, and then the positive battery lead 2.
3. Remove: 
Battery band...

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BATTERY INSPECTION AND CHARGING
ÅRelationship between the open-circuit voltage
and the charging time at 20 ˚C (68 ˚F)
(These values vary with the temperature, the
condition of the battery plates, and the electro-
lyte level.)
ıOpen-circuit voltage
ÇCharging time (hours)
ÎTime (minutes)
‰Charging condition of the battery
ÏAmbient temperature 20 ˚C (68 ˚F)
aCharging
bCheck the open-circuit voltage.
5. Charge: 
Battery 
(refer to the appropriate charging
method illustration)
WARNING
Do not...

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BATTERY INSPECTION AND CHARGING
Before removing the battery charger lead
clips from the battery terminals, be sure
to turn off the battery charger. 
Make sure the battery charger lead clips
are in full contact with the battery termi-
nal and that they are not shorted. A cor-
roded battery charger lead clip may
generate heat in the contact area and a
weak clip spring may cause sparks. 
If the battery becomes hot to the touch at
any time during the charging process,
disconnect the...

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BATTERY INSPECTION AND CHARGING
Charging method using a variable voltage charger 

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BATTERY INSPECTION AND CHARGING
Charging method using a constant voltage charger