Yamaha Wr 450 F Owners Manual

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CHASREAR SHOCK ABSORBER
2. Tighten:
Adjuster 1 
3. Adjust:
Spring length (installed) a 
* For EUROPE, AUS, NZ and ZA
NOTE:
The length of the spring (installed) changes
1.5 mm (0.06 in) per turn of the adjuster.
ACHTUNG:CAUTION:
Never attempt to turn the adjuster beyond
the maximum or minimum setting.
4. Tighten:
Locknut 1 
Rear shock absorber
1. Install:
Dust seal 1 
O-ring 2 
Collar 3 
NOTE:
Apply the molybdenum disulfide grease on
the bearing.
Apply the lithium soap base grease on the...

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CHASREAR SHOCK ABSORBER
2. Install:
Bush 1 
Collar 2 
Dust seal 3 
NOTE:
Apply the molybdenum disulfide grease on
the bearing.
Apply the lithium soap base grease on the
bush, collars and dust seals.
Install the dust seals with their lips facing
outward.
3. Install:
Rear shock absorber
4. Install:
Bolt (rear shock absorber-frame) 1 
Nut (rear shock absorber-frame) 2 
NOTE:
Apply the molybdenum disulfide grease on the
bolt.
5. Install:
Bolt (rear shock absorber-relay arm) 1
Nut (rear...

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CHAS
8. Install:
Plastic band 1 
Starting circuit cut-off relay coupler 2 
Taillight coupler 3 
Locking tie 4
3
2
1
4
REAR SHOCK ABSORBER 

 
6 - 1
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ELECTRICAL COMPONENTS AND WIRING DIAGRAM 
EC600000 
ELECTRICAL 
EC610000 
ELECTRICAL COMPONENTS AND WIRING DIAGRAM 
EC611000 
ELECTRICAL COMPONENTS 
1  
Headlight  
2  
“ENGINE STOP”
button  
3  
Clutch switch  
4 
Diode 
5 
Starter relay diode 
6 
TPS (throttle posi-
tion sensor) 
7 
Starter relay 
8 
Fuse 
9 
Starting circuit
cut-off relay 
0  
Taillight  
A  
Neutral switch  
B 
Starter motor  
C 
AC magneto 
D 
Rectifier/regulator 
E 
Ignition coil 
F 
Spark plug 
G 
Start switch 
H...

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6 - 2 
MAP-CONTROLLED CDI UNIT
MAP-CONTROLLED CDI UNIT 
A map-controlled, CDI ignition system is used in the WR450F.
The microcomputer in the CDI unit detects the engine speed and throttle position, thus determining
the optimum ignition timing through the entire operating range. In this way, quick throttle response
can be achieved according to various riding conditions.
CDI unit
Throttle position sensor
Pickup coil AC magneto rotorIgnition coil
 
 
Function of Component 
  
Component Function...

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6 - 3 
IGNITION SYSTEM 
EC620000 
IGNITION SYSTEM 
INSPECTION STEPS 
Use the following steps for checking the possibility of the malfunctioning engine being attributable to
ignition system failure and for checking the spark plug which will not spark. 
*1 marked: Refer to “FUSE INSPECTION” section in the CHAPTER 3.
*2 marked: Refer to “BATTERY INSPECTION AND CHARGING” section in the CHAPTER 3.
*3 marked: Only when the ignition checker is used.
NOTE:
 
 
Remove the following parts before...

 
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IGNITION SYSTEM 
SPARK GAP TEST 
1. Disconnect the ignition coil from spark
plug.
2. Remove the ignition coil cap.
3. Connect the dynamic spark tester  
1  
(ignition checker  
2 
) as shown. 
 
Ignition coil  
3 
  
 
Spark plug  
4 
  
Å 
For USA and CDN 
ı 
Except for USA and CDN 
4. Kick the kickstarter.
5. Check the ignition spark gap.
6. Start engine, and increase spark gap until
misfire occurs. (for USA and CDN only) 
Minimum spark gap:
6.0 mm (0.24 in)
Å
ı
 
COUPLERS, LEADS AND...

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–+ELECIGNITION SYSTEM
MAIN SWITCH INSPECTION
1. Inspect:
Main switch conduct
Continuous while the main switch is moved to
“OFF” → Replace.
Not continuous while the main switch is moved
to “ON” → Replace.
2. Inspect:
Main switch indicator light
Use 12 V battery.
Indicator light does not come on → Replace.
3. Inspect:
Rubber part a
Tears/damage → Replace. Tester (+) lead → Red lead 1 
Tester (–) lead → Brown lead 2 
R
1Br
2Tester selector 
position
ON
Ω × 1
OFF
Battery (+) lead → Red/Black lead 1...

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–+ELECIGNITION SYSTEM
3. Inspect:
Secondary coil resistance
Out of specification → Replace.
4. Inspect:
Sealed portion of ignition coil a
Spark plug terminal pin b
Threaded portion of spark plug c
Wear → Replace.
AC MAGNETO INSPECTION
1. Inspect:
Pick-up coil resistance
Out of specification → Replace. Tester (+) lead → Orange lead 1 
Tester (–) lead → Spark plug terminal 2 
Secondary coil 
resistanceTester selector 
position
4.6 ~ 6.8 kΩ at 
20 ˚C (68 ˚F)kΩ × 1
Tester (+) lead → Red lead 1...

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ELECTRIC STARTING SYSTEM
STARTING CIRCUIT CUT-OFF SYSTEM 
OPERATION
If the main switch is set to “ON”, the starter
motor can only operate if at least one of the
following conditions is met: 
The transmission is in neutral (the neutral
switch is closed). 
The clutch lever is pulled to the handlebar
(the clutch switch is closed).
The starting circuit cut-off relay prevents the
starter motor from operating when neither of
these conditions has been met. In this
instance, the starting circuit...