Checking The Ignition Spark Gap; Checking The Spark Plug Cap - Yamaha YZ450FN 2022 Owner's Service Manual

No continuity
Positive tester probe 
Blue/Green "1"
Negative tester probe  Blue
"2"
Continuity
Positive tester probe  Blue "2"
Negative tester probe 
Blue/Green "1"
No continuity
Positive tester probe 
Brown/White, Brown "3"
Negative tester probe 
Blue/Green, Blue/White "4"
Continuity
Positive tester probe 
Blue/Green, Blue/White "4"
Negative tester probe 
Brown/White, Brown "3"
No continuity
Positive tester probe 
Blue/Black "5"
Negative tester probe
Blue/Red "6"
Continuity
Positive tester probe 
Blue/Red "6"
Negative tester probe 
Blue/Black "5"
a. Disconnect the diode from the wire har-
ness.
b. Connect the digital circuit tester () to the
diode coupler as shown.
c. Check the diode for continuity.
d. Check the diode for no continuity.
1
L/G Br/W,Br
L/G,
L
L/W
2
A. Diode 1
B. Diode 2
C. Diode 3
EAM30294

CHECKING THE IGNITION SPARK GAP

1. Check:
• Ignition spark gap
Out of specification  Perform the ignition
3 5
L/B
L/R
4 6
8-48
ELECTRICAL COMPONENTS
system troubleshooting, starting with step (5).
Refer to "TROUBLESHOOTING" on page
8-3.
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" as
shown.
Ignition checker
90890-06754
Oppama pet–4000 spark checker
YM-34487
c. Crank the engine, and measure the igni-
tion spark gap "a".
2. Spark plug cap
d. Crank the engine, and gradually increase
the spark gap until a misfire occurs.
EAM30295

CHECKING THE SPARK PLUG CAP

1. Remove:
• Spark plug cap
(from the spark plug lead)
2. Check:
• Spark plug cap resistance
Out of specification  Replace.
Resistance
7.50–12.50 k
a. Connect the digital circuit tester () to the
spark plug cap.