www.kayomoto.us
- 40 -
Check the valve for bending, burns, or abnormal wear on the
valve stem, and measure the valve stem outer diameter.
Maintenance limit value:
Intake: φ4.96mm
Exhaust: φ4.94mm
Contact surface width maintenance limit value: 1.5mm
Note:
If the valve contact surface is rough, the
abrasion is uneven, or the valve seat is not in
proper contact, the sealing performance cannot
be guaranteed, and the valve should be replaced.
Measure the free length of the valve spring
：
48.35mm
Maintenance limits (air intake and output)
spring
：
47.5 mm
Inspection of swing arm and swing arm shaft
Check the swing arm and axial clearance. If it worn and tear seriously or swing arm roller axial clearance is too
large, please replace new swing arm.
Check swing arm axle, if it worn seriously, replace new axle.
Inspection of camshaft components
1.check the camshaft surface condition and bearing at both end, if surface has severe worn or damage or bearing
works inflexible, replace new components.
2.
Check if NC250 camshaft pressure relief valve block combination has cracks, fracture etc, and whether the
pressure relief valve centrifugal block and the pressure relief valve spindle shaft are loosen, if yes replace pressure
relief valve block combination.
Inspection of cylinder head
