Yamaha YZ450F, Owner'S Service Manual

Page: 584 / 650

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
(igni-
tion checker
2
) as shown.
• Ignition coil
3
• Spark plug
4
È
For USA and CDN
É
Except for USA and CDN
4. Kick the kick starter.
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)
È
É
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 fit-
ted
Push in the ignition coil until it closely
contacts the spark plug hole in the cylin-
der head cover.
EC625001
“ENGINE STOP” BUTTON INSPECTION
1. Inspect:
• “ENGINE STOP” button conduct
No continuity while being pushed
→
Replace.
Continuity while being freed
→
Replace.
Tester (+) lead
→
Black/White lead
1
Tester (–) lead
→
Black lead
2
B/W
1
B
2
Tester selec-
tor position
PUSH IN
Ω ×
1
FREE
1 2
B/W B