Suzuki GN125F, Service Manual

Page: 40 / 148

E N G I N E
3-9
ROCKER ARM
H
09900 20605: Caliper gauge -
09900-22302: Plastigage (0.051 – 0.152 mm)
Check the inside diameter of the valve rocker arm and wear
of the camshaft contacting surface.
The camshaft should be checked for runout and also for
wear of cams and journals if the engine has been noted
to produce abnormal noise or vibration or a lack of output
power.
Worn-down cams are often the cause of mistimed valve
operation resulting in reduced output power. The limit of cam
wear is specified for both intake and exhaust cams in terms of
cam height
, which is to be measured with a micrometer.
Replace camshafts if found it worn down to the limit.
Determine whether each journal is worn down to the limit or
not by measuring camshaft journal oil clearance with the
camshaft installed.
Use the plastigage to read the clearance at the widest
portion, install the cylinder head cover and tighten the
cylinder head cover bolts to the specified torque.
Remove the cylinder head cover and measure the width of
the compressed plastigage using the envelope scale. This
measurement should be taken at the widest part of the
compressed plastigage.
CAMSHAFT
CAMSHAFT JOURNAL WEAR
09900-20202: Micrometer (25-50 mm)
Rocker arm shaft O.D. (IN and EX): 12.0-12.018 mm
Camshaft journal oil clearance limit: 0.15 mm
Cam height H limit: IN.: 33 35mm EX.: 33.0 mm
.
If the camshaft journal oil clearance measured exceeds the
limit, measure the outside diameter of camshaft.
Replace either the cylinder head set or the camshaft if the
clearance is incorrect.
09900-20205: Micrometer (0-25 mm)
Camshaft journal O.D.: 21.970-21.991 mm
H