Honda CBR125R, Owner'S Manual

Page: 210 / 430

CYLINDER HEAD/VALVES
8-22
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
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
guides.
HAND
LAPPING TOOL
COTTERS
OUTER SPRING
SPRING SEAT
STEM SEAL
VALVE GUIDE
INTAKE VALVE
EXHAUST VALVE
INNER SPRING
RETAINER
SPARK PLUG
CYLINDER HEAD
INSULATOR
O
2
SENSOR
To avoid damage to
the seal, turn the
valve slowly when
inserting.
SPRING RETAINER
VALVE
STEM SEAL
SPRING SEAT
OUTER SPRING
INNER SPRING