Engine Block - Honda GX 120 Tech Manual

( Japan heads may be identified by the casting mark shown in photo above)
C. Measure from surface of head to lowest machined area in the bowl of the port. This dimension will be:
Intake:
Exhaust:
D. Thickness of head. This will be measured from valve cover surface to head gasket surface at the side at a position
in line with upper intake & exhaust flange bolt.
Maximum
Minimum
Note: Most heads in the field have a thickness of 2.914.
INTAKE AND EXHAUST PORTS
A. Ports will be "as cast" and in factory machined condition and there must be no addition or subtraction of metal or
any other substance to the inside or outside of the cylinder head.
B. No alterations of any kind to be made to the intake or exhaust port.
C. This includes any grinding, polishing, etching, sand blasting or glass beading to interior surface.
D. Valve seats must be a stock single 45-degree angle. Multi angle valve seats are not permitted. Valve seats must not
be replaced.
E. Intake and Exhaust ports at valve:
Intake:
Exhaust:
Note: Cleaning of the combustion chamber or changing the finish of such chamber is illegal.

ENGINE BLOCK

1.064" maximum
1.010" maximum
2.917"
2.911"
maximum 0.752" minimum 0.745"
maximum 0.675" minimum 0.665"
R|K
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