Honda CBR125R, Руководство пользователя

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CYLINDER HEAD/VALVES
8-18
Measure each valve guide I.D. and record it.
Subtract each valve stem O.D. from the correspond-
ing guide I.D. to obtain the stem-to-guide clearance.
If the stem-to-guide clearance exceeds the service
limit, determine if a new guide with standard
dimensions would bring the clearance within toler-
ance.
If so, replace any guides as necessary and ream to
fit.
If the stem-to-guide clearance exceeds the service
limit with a new guide, also replace the valve.
Inspect and reface the valve seats whenever the
valve guides are replaced (page 8-19).
VALVE GUIDE REPLACEMENT
Refinish the valve seats whenever the valve guides
are replaced to prevent uneven seating.
Chill new valve guides in a freezer section of refrig-
erator for about an hour.
Heat the cylinder head to 130 – 140
°
C (266 – 284
°
F)
with a hot plate or oven. Do not heat the cylinder
head beyond 150
°
C (302
°
F). Use temperature indica-
tor sticks, available from welding supply stores, to
be sure the cylinder head is heated to the proper
temperature.
To avoid burns, wear insulated gloves when han-
dling the heated cylinder head.
Support the cylinder head and drive out the valve
guides from the combustion chamber side of the
cylinder head.
SERVICE LIMIT: IN/EX: 5.04 mm (0.198 in)
SERVICE LIMITS: IN: 0.065 mm (0.0026 in)
EX: 0.075 mm (0.0030 in)
Do not use a torch
to heat the cylinder
head; it may cause
warping.
TOOL:
Valve guide driver, 5.0 mm
07942-8920000
VALVE GUIDE DRIVER