Yamaha 2004 WR250FS Owner's Service Manual page 113

IGNITION TIMING CHECK
2. Attach:
• Timing light
• Inductive tachometer
To the ignition coil lead (orange lead 1).
1
3. Adjust:
• Engine idling speed
Refer to "ENGINE IDLING SPEED
ADJUSTMENT" section.
4. Check:
• Ignition timing
Visually check the stationary pointer a is
within the firing range b on the rotor.
Incorrect firing range → Check rotor and
pickup assembly.
5. Install:
• Timing mark accessing screw
3 - 48
INSP
ADJ
Timing light:
YM-33277-A/90890-03141