Yamaha Wr 450 F Owners Manual

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6 - 8
ELECTRIC STARTING SYSTEM
INSPECTION STEPS
If the starter motor will not operate, use the following inspection steps.
*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: Refer to “MAIN SWITCH INSPECTION” section.
*4 marked: Refer to “NEUTRAL SWITCH INSPECTION” section.
NOTE:
Remove the following parts before inspection.
1) Seat
2) Rear fender
Use 12 V battery in this inspection.
Use the following special tools in this inspection.
Pocket tester:
YU-3112-C/90890-03112
*1 Check fuseReplace fuse and 
check wire harness.
*2 Check battery Recharge or replace.
Check each coupler and 
wire connection.Repair or replace.
*3 Check main switch. Replace.
Check starter motor 
operation.Repair or replace.
Check starting circuit 
cut-off relay.Replace.
Check starter relay. Replace.
*4 Check neutral switch. Replace.
Check clutch switch. Replace.
Check diode. Replace.
Check start switch. Replace.
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
No good
No good
No good
No good
No good
No good
No good
No good
No good
No good
No good 
						

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–+ELECELECTRIC STARTING SYSTEM
EC624000
COUPLERS AND LEADS CONNECTION 
INSPECTION
1. Check:
Couplers and leads connection 
Rust/dust/looseness/short-circuit → 
Repair or replace.
STARTER MOTOR OPERATION
1. Connect the positive battery terminal 1
and starter motor lead 2 with a jumper
lead 3.
Not operate → Repair or replace the
starter motor.
WARNING
A wire that is used as a jumper lead must
have at least the same capacity or more
as that of the battery lead, otherwise the
jumper lead may burn.
This check is likely to produce sparks,
therefore make sure nothing flammable is
in the vicinity.
STARTING CIRCUIT CUT-OFF RELAY 
INSPECTION 
1. Remove:
Starting circuit cut-off relay
2. Inspect:
Starting circuit cut-off relay conduct 
Use 12 V battery.
Battery (+) lead → Blue/Black lead 1 
Battery (–) lead → Brown lead 2 
Tester (+) lead → Blue/White lead 3 
Tester (–) lead → Black lead 4 
L/W
3B
4
Tester selec-
tor position
Connected 
to battery
Ω × 1Not 
connected 
to battery
2 4
3
1 
						

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–+ELECELECTRIC STARTING SYSTEM
STARTER RELAY INSPECTION
1. Remove:
Starter relay
2. Inspect:
Starter relay conduct
Use 12 V battery.
Continuous while not connected to the battery
→ Replace.
Not continuous while connected to the battery
→ Replace.Battery (+) lead → 
Starter relay terminal 1
Battery (–) lead → 
Starter relay terminal 2
Tester (+) lead → 
Starter relay terminal 3
Tester (–) lead → 
Starter relay terminal 4
Ter-
minal
3
Ter-
minal
4Tester selec-
tor position
Connected 
to battery
Ω × 1Not 
connected 
to battery
CLUTCH SWITCH INSPECTION
1. Inspect:
Clutch switch continuity
No continuous while being pulled → Replace.
Continuous while being freed → Replace. Tester (+) lead → Black lead 1 
Tester (–) lead → Black lead 2 
B
1B
2Tester selec-
tor position
PULL
Ω × 1
FREE 
						

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–+ELECELECTRIC STARTING SYSTEM
DIODE INSPECTION
1. Remove the diode from wire harness.
2. Inspect:
Diode continuity
Use pocket tester (tester selection posi-
tion Ω × 1) 
Incorrect continuity → Replace. Tester (+) → 
Blue/Red terminal 1
Tester (–) → 
Sky blue terminal 2Continuous
Tester (+) → 
Blue/Red terminal 1
Tester (–) → 
Blue/Yellow terminal 3Continuous
Tester (+) → 
Sky blue terminal 2
Tester (–) → 
Blue/Red terminal 1No 
continuous
Tester (+) → 
Blue/Yellow terminal 3
Tester (–) → 
Blue/Red terminal 1No 
continuous
23
1
START SWITCH INSPECTION
1. Inspect:
Start switch continuity
No continuous while being pushed → Replace.
Continuous while being freed → Replace.
2. Inspect:
Rubber part a
Tears/damage → Replace. Tester (+) lead → Black lead 1 
Tester (–) lead → Black lead 2 
B
1B
2Tester selec-
tor position
PUSH IN
Ω × 1
FREE
a 
						

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–+ELECELECTRIC STARTING SYSTEM
STARTER MOTOR
0
9
56
7
5 0 8
9
4
3
2
1
New
New
New
B
5
1
Extent of removal:1 Starter motor disassembly
Extent of removal Order Part name Q’ty Remarks
STARTER MOTOR REMOVAL 
Preparation for removal Drain the engine oil. Refer to “ENGINE OIL REPLACEMENT”
section in the CHAPTER 3.
Crankcase cover (left) Refer  to “AC MAGNETO AND
STARTER CLUTCH” section in the
CHAPTER 4.
1 Starter motor 1
STARTER MOTOR DISASSEM-
BLY
1Starter motor front cover 1
2Washer (starter motor front
cover)1
3Plain washer 1
4Circlip 1
5O-ring
3
1 
						

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–+ELECELECTRIC STARTING SYSTEM
0
9
56
7
5 0 8
9
4
3
2
1
New
New
New
B
5
1
Extent of removal Order Part name Q’ty Remarks
6Starter motor yoke 1
7Armature assembly 1
8Starter motor rear cover 1
9Brush 2
0Brush spring 2
1 
						

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–+ELECELECTRIC STARTING SYSTEM
INSPECTION AND REPAIR
1. Check: 
Commutator 
Dirt → Clean with 600 grit sandpaper.
2. Measure: 
Commutator diameter a 
Out of specification → Replace the
starter motor.
3. Measure: 
Mica undercut a 
Out of specification → Scrape the mica
to the proper measurement with a
hacksaw blade which has been
grounded to fit the commutator.
NOTE:
The mica must be undercut to ensure proper
operation of the commutator. 
Min. commutator diameter 
16.6 mm (0.65 in)
Mica undercut 
1.5 mm (0.06 in)
4. Measure: 
Armature assembly resistances (com-
mutator and insulation) 
Out of specification → Replace the
starter motor.
Measure the armature assembly resis-
tances with the pocket tester.
Pocket tester 
YU-03112-C/90890-03112
Armature assembly
Commutator resistance 1
0.0117 ~ 0.0143 Ω at 20 ˚C 
(68 ˚F)
Insulation resistance 2
Above 1 MΩ at 20˚C (68 ˚F)
If any resistance is out of specification,
replace the starter motor. 
						

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–+ELECELECTRIC STARTING SYSTEM
5. Measure: 
Brush length a 
Out of specification → Replace the
brushes as a set.
Min. brush length
3.5 mm (0.14 in)
6. Measure:
Brush spring force
Out of specification → Replace the
brush springs as a set.
Brush spring force
3.92 ~ 5.88 N 
(400 ~ 600 gf, 14.1 ~ 21.2 oz)
ASSEMBLY
1. Install:
Brush spring 1 
Brush 2 
2. Install:
Armature assembly 1 
Install while holding down the brush
using a thin screw driver.
CAUTION:
Be careful not to damage the brush during
installation. 
						

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–+ELECELECTRIC STARTING SYSTEM
3. Install:
O-ring 1 
Starter motor yoke 2 
NOTE:
Align the match mark a on the starter motor
yoke with the match mark b on the starter
motor rear cover.
Install the starter motor yoke with its groove
c facing rear cover.
a
b
c 2
1
NewNew
4. Install:
O-ring 1 
Circlip
Plain washer 2 
Washer (starter motor front cover) 3 
Starter motor front cover 4 
NOTE:
For installation, align the projections on the
washer with the slots in the front cover.
Align the match mark a on the starter motor
yoke with the match mark b on the starter
motor front cover.
ba 4
3
21
NewNew
5. Install:
Bolt 1 
O-ring 2 
NOTE:
Apply the lithium soap base grease on the O-
ring.
New 
						

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CHARGING SYSTEM
EC680000
CHARGING SYSTEM
EC681001
INSPECTION STEPS
If the battery is not charged, use the following inspection steps.
*1 marked: Refer to “FUSE INSPECTION” section in the CHAPTER 3.
*2 marked: Refer to “BATTERY INSPECTION AND CHARGING” section in the CHAPTER 3.
NOTE:
Remove the following parts before inspection.
1) Seat
2) Fuel tank
Use the following special tool in this inspection.
Pocket tester:
YU-3112-C/90890-03112Inductive tachometer:
YU-8036-B
Engine tachometer:
90890-03113
*1 Check fuse.Replace fuse and 
check wire harness.
*2 Check battery. Recharge or replace.
Check each coupler and 
wire connection.Repair or replace.
Check charging voltage.Charging system is 
good.
Check AC magneto. Charging coil Replace.
Replace rectifier/regulator.
OK
OK
OK
No good
OK
No good
No good
No good
No good
OK