Yamaha YZ450F(T) Owner's Service Manual page 577

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.
Spark gap test
No spark
Check entire ignition
system for connection.
(couplers, leads and
ignition coil)
OK
Check "ENGINE STOP"
button.
OK
Check ignition coil.
OK
Check CDI magneto.
OK
Check neutral switch.
OK
Replace CDI unit.
*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
IGNITION SYSTEM
Spark
No good
No good
Primary coil
Secondary coil
Pick-up coil
Source coil
No good
6 - 3
ELEC
*Clean or replace
Repair or replace.
No good
No good
No good
No good
Repair or replace.
Pocket tester:
YU-3112-C/90890-03112
– +
spark plug.
Replace.
Replace.
Replace.
Replace.
Replace.