2003 YAMAHA WR 450F check oil

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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 inspection.
1) Seat
2) Fuel tank

Use the following special tools in this inspection.
Dynamic spark tester:
YM-34487
Ignition checker:
90890-06754
Pocket tester:
YU-3112-C/90890-03112
*1 Check fuse.Replace fuse and
check wire harness.
*2 Check battery Recharge or replace.
Spark gap test*3 Clean or replace
spark plug.
Check entire ignition
system for connection.
(couplers, leads and
ignition coil)Repair or replace.
Check “ENGINE STOP”
button.Replace.
Check main switch. Replace.
Check ignition coil. Primary coil Replace.
Secondary coil Replace.
Check AC magneto. Pick-up coil Replace.
Check neutral switch. Repair or replace.
Replace CDI unit.
OK
OK
No spark
OK
OK
OK
OK
OK
OK
Spark
No good
No good
No good
No good
No good
No good
No good
No good
No good

6 - 4
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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 IGNITION COIL
CONNECTION INSPECTION
1. Check:

Couplers and leads connection
Rust/dust/looseness/short-circuit →
Repair or replace.
Ignition coil and spark plug as they are
fitted
Push in the ignition coil until it closely
contacts the spark plug hole in the cyl-
inder head cover.
EC625001
“ENGINE STOP” BUTTON INSPECTION
1. Inspect:
“ENGINE STOP” button conduct
No continuity while being pushed → Replace.
Continuity 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 selector
position
PUSH IN
Ω × 1
FREE
a

6 - 6
–+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
Tester (–) lead → White lead 2
Pick-up coil
resistanceTester selector
position
248 ~ 372 Ω at
20 ˚C (68 ˚F)Ω × 100
RW
12
NEUTRAL SWITCH INSPECTION
1. Inspect:
Neutral switch conduct
No continuity while in neutral → Replace.
Continuity while in gear → Replace.
EC628000
CDI UNIT INSPECTION
Check all electrical components. If no fault is
found, replace the CDI unit. Then check the
electrical components again.Tester (+) lead → Sky blue lead 1
Tester (–) lead → Ground 2
Sb
1GroundTester selec-
tor position
NEUTRALΩ × 1IN GEAR
–+ Ω×1
1
2L/W Sb

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6 - 17
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

6 - 18
–+ELECCHARGING SYSTEM
EC624000
COUPLERS AND LEADS CONNECTION
INSPECTION
1. Check:
Couplers and leads connection
Rust/dust/looseness/short-circuit →
Repair or replace.
CHARGING VOLTAGE INSPECTION
1. Start the engine.
2. Inspect:
Charging voltage
Out of specification → If no failure is
found in checking the source coil resis-
tance, replace the rectifier/regulator.
Tester (+) lead → Red lead 1
Tester (–) lead → Black lead 2
Charging
voltageTester selector
position
14.1 ~ 14.9 V at
5,000 r/minDCV-20
R
BW Y1
2
3. Inspect:
Charging coil resistance
Out of specification → Replace.
Tester (+) lead → White lead 1
Tester (–) lead → Ground 2
Charging coil
resistanceTester selector
position
0.288 ~ 0.432 Ω
at 20 ˚C (68 ˚F)Ω × 1

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6 - 19
TPS (THROTTLE POSITION SENSOR) SYSTEM
EC690000
TPS (THROTTLE POSITION SENSOR) SYSTEM
INSPECTION STEPS
If the TPS will not operate, use the following inspection steps.
NOTE:
Use the following special tools in this inspection.
Pocket tester:
YU-3112-C/90890-03112Inductive tachometer:
YU-8036-B
Engine tachometer:
90890-03113
Check entire ignition
system for connection.Repair or replace.
Check TPS. TPS coil Replace.
Check CDI unit.TPS input
voltageReplace.
OK
OK
No good
No good
No good

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–+ELECTPS (THROTTLE POSITION SENSOR) SYSTEM
HANDLING NOTE
CAUTION:
Do not loosen the screws {TPS (throttle
position sensor)} 1 except when changing
the TPS (throttle position sensor) due to
failure because it will cause a drop in
engine performance.
1
EC624000
COUPLERS AND LEADS CONNECTION
INSPECTION
1. Check:
Couplers and leads connection
Rust/dust/looseness/short-circuit →
Repair or replace.
TPS COIL INSPECTION
1. Inspect:
TPS coil resistance
Out of specification → Replace.
2. Loosen:
Throttle stop screw 1
NOTE:
Turn out the throttle stop screw until the throt-
tle shaft is in the full close position.Tester (+) lead → Blue lead 1
Tester (–) lead → Black lead 2
TPS coil
resistanceTester selector
position
4 ~ 6 kΩ at
20 ˚C (68 ˚F)kΩ × 1

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–+ELECTPS (THROTTLE POSITION SENSOR) SYSTEM
3. Inspect:
TPS coil variable resistance
Check that the resistance in increased
as the throttle grip is moved from the
full close position to the full open posi-
tion.
Out of specification → Replace.
Tester (+) lead → Yellow lead 1
Tester (–) lead → Black lead 2
TPS coil variable
resistanceTester selec-
tor position
Full closedFull opened
kΩ × 1 0 ~ 2 kΩ at
20 ˚C
(68 ˚F)4 ~ 6 kΩ at
20 ˚C
(68 ˚F)
TPS REPLACEMENT AND ADJUSTMENT
1. Remove:
TPS coupler
Screw (TPS) 1
TPS 2
NOTE:
Loosen the screws (TPS) using the T25 bit.
2. Replace:
TPS
3. Install:
TPS 1
Screw (TPS) 2
TPS coupler
NOTE:
Align the slot a in the TPS with the projec-
tion b on the carburetor.
Temporarily tighten the screws (TPS).
12
21
b
a