Yamaha yz450f 2012 Service Manual

7-3
IGNITION SYSTEM
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.
*marked: Only when the ignition checker is used.
• Remove the following parts before inspection.
1. Seat
2. Fuel tank
• Use the following special tools in this inspection.
Spark gap test
Spark → • *Clean or replace spark plug.
• Check the connection of the spark plug cap to the
spark plug.
No spark ↓
Check entire ignition system for connection.
(couplers, leads and ignition coil)
No good →
Repair or replace.
OK ↓
Check engine stop switch. No good → Replace.
OK ↓
Check ignition coil. (primary coil and secondary
coil)
No good →
Replace.
OK ↓
Check AC magneto. (crankshaft position sensor
and stator coil)
No good →
Replace.
OK ↓
Replace ECU.
Dynamic spark tester:
YM-34487
Ignition checker:
90890-06754
Pocket tester:
YU-03112-C/90890-03112

Yamaha yz450f 2012 Specifications

General

Bore x Stroke	97.0mm x 60.8mm
Compression Ratio	12.5:1
Fuel Delivery	Fuel Injection
Transmission	5-speed
Final Drive	Chain
Tires Front	80/100-21
Tires Rear	120/80-19
Wheelbase	58.7 in
Trail	4.6 in
Fuel Capacity	1.6 gal
Wet Weight	245 lb
Engine Type	Liquid-cooled, 4-stroke, DOHC, 4-valve
Ignition	TCI
Suspension Front	Telescopic fork, 12.2 in travel
Suspension Rear	Swingarm, 12.4 in travel
Brakes Front	Hydraulic single disc brake, 250mm
Brakes Rear	Single disc, 245 mm