Yamaha WR450F(R) Owner's Service Manual page 114

IGNITION TIMING CHECK
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IGNITION TIMING CHECK
1. Remove:
Timing plug 1
G
2. Attach:
Timing light
G
Inductive tachometer
G
To the ignition coil lead (orange lead
1).
Timing light:
YM-33277-A/90890-03141
Inductive tachometer:
YU-8036-B
Engine tachometer:
90890-03113
3. Check:
Ignition timing
G
Checking steps:
Start the engine and let it warm up. Let the
G
engine run at the specified speed.
Adjust the engine idling speed.
G
Refer to "IDLE SPEED ADJUSTMENT"
section.
Visually check the stationary pointer a is
G
within the firing range b on the rotor.
Incorrect firing range → Check rotor and
pickup assembly.
4. Install:
Timing plug
G
INSP
ADJ