Shibaura ST330, Workshop Manual

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2. DISASSEMBLY AND INSPECTION OF ENGINE MAIN PARTS
* Cautions before start
1) Check the cylinder block and cylinder head for wear, leakage and damage.
2) Remove deposit in oil holes of each part with air and check for clogging.
3) Wash each part well to remove dust, contaminated oil, carbon, and other foreign matter.
4) Remove carbon deposited on the piston, cylinder head, valves, etc. carefully not to damage parts. (Great care is necessary
specifically for aluminum alloy parts.)
5) Valves, pistons, connecting rods, metals and other parts which are to be combined as specified should be attached match
marks beforehand to prevent confusion.
1) Rocker arm ass’y
Disassembly
(1) Thread an 8 mm bolt into the front and of the rocker shaft
and slowly withdraw rocker shaft while at the same time
removing the rocker arms, springs and shims.
1. M8 bolt
2. Rocker arm shaft
3. Rocker arm
4. Spring
5. Shim
Inspection and service
(1) Using a micrometer, check outside diameter of the rocker
arm shaft. If the shaft is worn exceeding service limit,
replace it with new one.
Wear of rocker arm shaft (ø)
Standard assembling value Service limit
N843 14.95
－
14.97 14.87
(2) Measure the inside diameter of the rocker arm. Calculate
the clearance between the rocker arm and rocker arm shaft.
If the clearance is excessive, replace the part.
Clearance between rocker arm and rocker arm shaft (mm)
Standard assembling value Service limit
0.032 – 0.068 More than 0.2
(3) Check the valve cap-contact surface for uneven wear and
streaks. Correct curved surface with an oilstone or
grinder correctly if insignificant.
106Y
107Y
108Y