(1) To disassemble the rocker arm assembly, remove one spring retainer (26) and slide the end springs (25),
rocker arm assemblies (5), rocker arm brackets (8), and spacer springs (9) from the rocker arm shaft (15).
If possible, do not disturb the setting of the adjusting screws (6) and their hex nuts (7).
(2) Compress the valve springs (10) until the spring lock retainers (12) can be removed. Then disassemble the
valve rotators (11), valve springs (10), valves (20 and 21) and valve stem guides (23) from the cylinder head
(17).
Caution
When removing valves, arrange them in the order in which they are removed so
that they can be reinserted into the same valve ports during installation.
c. Cleaning and Inspection.
(1) Clean and inspect all valves carefully. See that carbon or other foreign matter is removed from the valve
head and stem. Inspect the end of the valve stem and face of each valve for pitting, scoring or warping. If
warped or excessively pitted or scored, replace the valve.
(2) Inspect valve springs for broken coils and make certain that they have adequate tension. Replace weak or
broken springs.
(3) Clean the oil holes in the rocker arm shaft thoroughly. To clean the inside of this hollow shaft, the expansion
plugs (27, fig. 57) must be removed. Make certain that the shaft is not bent or distorted. Replace shaft if
necessary.
(4) Thoroughly clean the oil holes in the rocker arms and bushings, and examine the bushings for wear.
Rocker arms and their bushings are serviced only as assemblies. Carefully inspect the valve contact face of
each rocker arm for excessive grooving or pitting. If such a condition is evident, the rocker arm must be
replaced.
(5) Clean the cylinder head casting and the head mounting surface of the crankcase with a cloth dampened in
cleaning solvent. It is very important that the mating surfaces of the cylinder head and crankcase block be
absolutely clean before installing the cylinder head.
d. Reassembly.
(1) Press the valve stem guides (23, fig. 57) down into place in the cylinder head (17) and insert the valves (20
and 21) up into their proper ports. Install the valve springs
131