Shibaura SG280E, Workshop Manual

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1. Cylinder head
1) Use the valve spring replacer to compress the valve
spring, and then remove the valve cotter , retainer
, spring , and valve .
2) Remove the valve guide seal , if necessary.
3) Check for cracks and damage on the cylinder head.
Valve stem route
Water jacket areas (channels) ⋅⋅⋅
Valve seats
⋅⋅⋅
Combustion chambers ⋅⋅⋅
4) Check for deformation on the bottom surface of the
cylinder head.
Insert a straight edge underneath the cylinder head,
and then insert a thickness gauge in locations A
through F shown in the figure on the right to take
measurements.
If the amount of deformation exceeds the required
repair level, use a surface grinder to make repairs.
Deformation in bottom of cylinder head (mm)
Assembly standard Required repair level
0.05 or less 0.12 or more
2-5 Disassembling, inspecting, and assembling
primary parts
Fig.2-5-1
Fig.2-5-2
Fig.2-5-3
Fig.2-5-4