Yamaha Motor YZ250 N/LC 2001 Manuel D'atelier Du Proprietaire page 208

IGNITION TIMING CHECK
EC372051
IGNITION TIMING CHECK
1. Remove:
9Cylinder head
Refer to "CYLINDER HEAD, CYLINDER
AND PISTON" section in the CHAPTER 4.
9Crankcase cover (left)
2. Attach:
9Dial gauge 1
9Dial gauge stand 2
3. Rotate the magneto rotor 1 until the piston
reaches top dead center (TDC). When this
happens, the needle on the dial gauge will
stop and reverse directions even though the
rotor is being turned in the same direction.
4. Set the dial gauge to zero at TDC.
5. From TDC, rotate the rotor clockwise until
the dial gauge indicates that the piston is at
a specified distance from TDC.
6. Check:
9Ignition timing
Punch mark a on rotor should be aligned
with punch mark b on stator.
Not aligned
3-39
INSP
ADJ
Dial gauge:
YU-3097/90890-01252
Stand:
YU-1256
Ignition timing (B.T.D.C.):
0.18 mm (0.007 in)
Adjust.