Honda CBR125R, Owner'S Manual

Page: 205 / 430

CYLINDER HEAD/VALVES
8-17
VALVE SPRING
Check the valve springs for fatigue or damage.
Measure the free length of the inner and outer valve
springs.
Replace the springs if they are shorter than the ser-
vice limits.
VALVE
Check that the valve moves smoothly in the guide.
Inspect each valve for bending, burning, scratches
or abnormal stem wear.
Measure and record each valve stem O.D.
VALVE GUIDE
Ream the valve guide to remove any carbon build-
up before measuring the guide I.D.
• Use cutting oil on the reamer during this opera-
tion.
• Take care not to tilt or lean the reamer in the
guide while reaming. Otherwise, the valves may
be installed slanted, causing oil leakage from the
stem seal and improper valve seat contact. This
may prevent valve seat refacing.
• Insert the reamer from the combustion chamber
side of the head and always rotate the reamer
clockwise.
SERVICE LIMITS: INNER: 31.0 mm (1.22 in)
OUTER: 34.0 mm (1.34 in)
INNER SPRING
OUTER SPRING
SERVICE LIMITS: IN: 4.863 mm (0.1915 in)
EX: 4.853 mm (0.1911 in)
VALVE
TOOL:
Valve guide reamer, 5.0 mm
07984-MA60001
VALVE GUIDE REAMER