Suzuki RM-Z250 Owner's Service Manual page 109

6-14 CYLINDER HEAD, CYLINDER AND PISTON
VALVE STEM DEFLECTION
• Lift the valve about 10 mm (0.39 in) from the valve seat.
• Measure the valve stem deflection in two directions, perpen-
dicular to each other, by positioning the dial gauge as shown.
• If the deflection measured exceeds the limit, then determine
whether the valve or the guide should be replaced with a new
one.
" Valve stem deflection (IN. & EX.):
Service Limit: 0.25 mm (0.010 in)
# 09900-20607: Dial gauge (1/100, 10 mm)
09900-20701: Magnetic stand
VALVE STEM WEAR
• If the valve stem is worn down to the limit, as measured with a
micrometer, replace the valve.
• If the stem is within the limit, then replace the guide.
• After replacing valve or guide, be sure to recheck the deflec-
tion.
NOTE:
If valve guides have to be removed for replacement after
inspecting related parts, carry out the steps shown in valve
guide servicing.
" Valve stem O.D.:
Standard (IN.) : 4.475 – 4.490 mm (0.1762 – 0.1768 in)
(EX.): 4.455 – 4.470 mm (0.1754 – 0.1760 in)
# 09900-20205: Micrometer (0 – 25 mm)
VALVE GUIDE SERVICING
• Using the valve guide remover, drive the valve guide out
toward the intake or exhaust camshaft side.
NOTE:
* Discard the removed valve guide subassemblies.
* Only oversized valve guides are available as replacement
parts. (Part No. 11115-10H70)
# 09916-43211: Valve guide remover/installer
• Re-finish the valve guide holes in cylinder head with the
reamer and handle.
When refinishing or removing the reamer from the
valve guide hole, always turn it clockwise.
# 09916-33320: Valve guide reamer (9.8 mm)
09916-34542: Reamer handle
CAUTION
Y Y Y
X X X