Yamaha YP250 Service Manual page 113

VALVES AND VALVE SPRINGS
YP402030
4. Measure:
S Spring tilt
5. Inspect:
S Spring contact face
6. Measure:
S Valve guide inside diameter
YP402010
7. Measure:
Stem-to-guide clearance =
Out of specification ! Replace the valve
guide.
EB402020
VALVE SEATS INSPECTION
1. Eliminate:
S Carbon deposits
2. Inspect:
S Valve seats
4-17
Out of specification ! Replace.
Spring tilt limit:
1.7 mm (2.5_)
Wear/Pitting/Scratches ! Replace.
Out of specification ! Replace.
Valve guide inside diameter:
Intake:
6.000 X 6.012 mm
<Limit: 6.05 mm>
Exhaust:
6.000 X 6.012 mm
<Limit: 6.05 mm>
Valve guide inside diameter –
Valve stem diameter
Stem-to-guide clearance limit:
Intake:
0.08 mm
Exhaust:
0.10 mm
(from the valve face and valve seat)
Pitting/wear ! Reface the valve seat.
ENG