Checking The Ignition Spark Gap; Checking The Spark Plug Cap; Checking The Ignition Coil - Yamaha YZ250F 2016 Owner's Service Manual

CHECKING THE IGNITION SPARK GAP

EAS1SM9334
1. Check:
• Ignition spark gap
Out of specification  Perform the ignition
system troubleshooting.
Refer to "TROUBLESHOOTING" on page 8-
4.
Minimum ignition spark gap
6.0 mm (0.24 in)
TIP
If the ignition spark gap is within specification,
the ignition system circuit is operating normally.
▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼
a. Remove the spark plug cap from the spark
plug.
b. Connect the ignition checker "1".
Ignition checker
90890-06754
Oppama pet-4000 spark checker
YM-34487
c. Crank the engine, and measure the ignition
spark gap "a".
2. Spark plug cap
d. Crank the engine, and gradually increase
the spark gap until a misfire occurs.
▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲

CHECKING THE SPARK PLUG CAP

EAS1SM9335
1. Remove:
• Spark plug cap
(from the spark plug lead)
2. Check:
• Spark plug cap resistance
Out of specification  Replace.
Resistance
10.00 k
ELECTRICAL COMPONENTS
▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼
a. Connect the pocket tester (  1k) to the
spark plug cap.
Pocket tester
90890-03112
Analog pocket tester
YU-03112-C
b. Measure the spark plug cap resistance.
▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲

CHECKING THE IGNITION COIL

EAS1SM9336
1. Disconnect:
• Ignition coil terminal
(from the sub wire harness)
• Spark plug cap
(from the ignition coil)
2. Check:
• Primary coil resistance
Out of specification  Replace.
Primary coil resistance
2.16–2.64 
▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼
a. Connect the pocket tester (  1) to the igni-
tion coil.
Pocket tester
90890-03112
Analog pocket tester
YU-03112-C
• Positive tester probe 
Ignition coil terminal 1 "1"
• Negative tester probe 
Ignition coil terminal 2 "2"
8-41