Service Manual

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4-10 ENGINE TOP END
l Check the cylinder head for cracks or other damage.
l Cracks not visible to the eye may be detected by coating the suspected
area with mixture of 25% kelosene and 75% light engine oil.
@Wipe the area dry and immediately apply a coating of zinc oxide
dissolved in wood alcohol. If a cracks is present, the coating will
become discolored at the defective area.
*If a cracks is present in the cylinder head, replace it.
l inspect the gasket surface for burrs and nicks.
0 Inspect the cylinder head for accumulation of rust, scale and lime in the
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water jacket (A).
*If this accumulation is observed, flush the cooling system (see
@CA
4
Flushing in Cooling System chapter).
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OClean and measure the diameter of the rocker shaft (A) with a
micrometer at several points.
*If the outside diameter is less than the service limit, replace the shaft.
Rocker ShaH Outside Diameter
Servke Limit: 11.949 mm (0.4704 in)
l Clean and inspect the rocker arm where it touches the push rod and
valve stem.
*If the contact points (A) are worn or damaged, replace the rocker arm.
0 Measure the inside diameter of the rocker arm bearing (B) at several
points using a dial bore gauge or inside micrometer.
*If the inside diameter is more than the service limit, replace the rocker
arm.
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Rocker Arm Bearing lnslde Diameter
Service Limit: 12.074 mm (0.4754 in)