Baja WD250U Service Manual page 163

• Press the valve on the valve race through
valve guide pipe to leave clear trace on the
valve.
• Remove the valve from cylinder cover
• When the valve contacts with valve race,
the reddle is marked on the valve from valve
race. Then can measure the contacting width of
valve and valve race.
Contacting width of
Valve and valve race
Intake 0.9~1.1mm
Exhaust (0.035~0.043mm)
• If the contacting width is too wide, too
narrow or not in the middle, it is necessary to
recorrect valve race.
4) Correct
• Valve race
Use reamers of 30°, 45°, and 60°
CAUTION:
Rotate the reamer with even force to avoid
cutting mark. And remove surplus part to get
ideal valve race.
Reamer used on each part
Part
A
B
C
Valve race correcting procedure
The contacting part [A] is in the middle
of valve face. But the contacting width is too
wide.
Reamer assy of valve race
Operate Reamer 30°
lightly Reamer 60°
162
Limit
1.6mm
(.063in)
Reamer
30°
45°
60°
Reamer
Reduce the
contacting width to 1.0mm
(0.04in)