head YAMAHA WR 450F 2003 Workshop Manual

6 - 4
–+ELEC

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 - 25
–+ELECLIGHTING SYSTEM
LIGHTS SWITCH INSPECTION
1. Inspect:
Lights switch conduct
No continuous while being → Replace.
Continuous while being OFF → Replace. Tester (+) lead → Yellow lead 1
Tester (–) lead → Blue lead 2
Y
1L
2Tester selec-
tor position
Ω × 1
OFF
AC MAGNETO INSPECTION
1. Inspect:
Lighting coil resistance
Out of specification → Replace.
RECTIFIER/REGULATOR INSPECTION
1. Connect the battery leads.
2. Start the engine.
3. Turn on the headlight and taillight by turn-
ing on the lights switch.
4. Inspect:
Out-put voltage
Out of specification → Replace rectifier/
regulator. Tester (+) lead → Yellow lead 1
Tester (–) lead → Ground 2
Lighting coil
resistanceTester selector
position
0.224 ~ 0.336 Ω
at 20 ˚C (68 ˚F)Ω × 1
Tester (+) lead → Yellow lead 1
Tester (–) lead → Black lead 2
Out-put voltageTester selector
position
13.0 ~ 14.0 V at
5,000 r/minACV-20
R
BW
Y1
2