Honda CBR125R Owner's Manual page 210

CYLINDER HEAD/VALVES
After cutting the seat, apply lapping compound to
the valve face and lap the valve using light pressure.
• Excessive lapping pressure may deform or dam-
age the seat.
• Change the angle of lapping tool frequently to
prevent uneven seat wear.
• Lapping compound can cause damage if it enters
between the valve stem and guide.
After lapping, wash any residual compound off the
cylinder head and valve.
Recheck the seat contact after lapping.
ASSEMBLY
COTTERS
OUTER SPRING
SPRING SEAT
VALVE GUIDE
O SENSOR
2
Clean the cylinder head assembly with solvent and
blow through all oil passages with compressed air.
Install the spring seats and new valve stem seals.
Lubricate each valve stem and stem end with
molybdenum oil solution.
Insert the intake and exhaust valves into the valve
To avoid damage to
guides.
the seal, turn the
valve slowly when
inserting.
8-22
SPARK PLUG
INTAKE VALVE
HAND
LAPPING TOOL
INNER SPRING
STEM SEAL
INSULATOR
CYLINDER HEAD
EXHAUST VALVE
VALVE
STEM SEAL
SPRING SEAT
INNER SPRING
SPRING RETAINER
RETAINER
OUTER SPRING