Honda GX 120 Tech Manual page 4

D. The starter cup that is behind the flywheel retaining nut can be cut away to leave only the flat washer back
piece that retains cooling fan.
E. The keyed end of the sun gear shaft may be shortened, drilled and tapped or machined for snap ring.
F. Heli-coiling threads for shrouds (all), valve cover, existing throttle mounting holes, oil drain, and fill holes,
one of the coil bolts, and side cover bolts is allowed. Dowel holes are not to be modified or relocated, also one
carburetor-mounting bolt.
G. Honing and deglazing of the bore is allowed.
H. Lapping the valves is allowed.
I. Blocking Air Flow: No device may be used that will/or appear that it may impede airflow into the engine
cooling system. This may require that the engine be run at a speed above idle by the tech personnel at the scale
after the car has qualified or raced.
CARBURETOR
GX160 CARBURETOR MAY BE USED IN HEAVY HONDA ONLY
(SEE GX160 MANUAL FOR CARB SPECS)
Remove Carburetor:
A. Check for restrictor, if applicable, and placement. Restrictor must be installed between carburetor and carburetor insulator
with stock Honda gasket on each side of restrictor. Only stock Honda insulator gasket between black plastic insulator and
head. Air passageway in insulator will not be altered in anyway. All Junior Honda's must use the blue QMA approved
slotted plate only. Failure to use proper restrictor plate, alteration of restrictor plate, or improper installation of plate in
designated classes is cause for immediate DQ and all applicable suspensions will be applied.
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B. Check for any alterations or worn parts that would allow additional air into engine: holes, slots, perforations,
spacers, loose bolts, warped flanges etc.
C. Carburetor identification number: BE 60 B Thai # BE 60 R UT-2#BE99A
D. Check carburetor for alterations. Upper choke shaft hole may be sealed with silicone type sealer.
E. Two stock Honda intake gaskets may be used between Carburetor and plastic insulator.
F. Carburetor Bore:
G. Carburetor venturi bore: 0.456" no go. This measurement is best made with a no go gauge but may be made using
a telescoping gauge as a no go.
Either Japanese or Thailand insulators may be used.
Gasket thickness: 0.025"maximum.
Restrictor thickness: 0.0625" maximum. No slotting of holes on any Honda restrictor.
Insulator gasket thickness: 0.025" maximum.
Novice Restrictor hole size: 0.3125"maximum (red).Plate must have QMA logo.
Junior Restrictor hole size: 0.4375"maximum (blue).Note blue plate only effective 5-31-10
plate must be dated 06-09 or newer (DQ and 30 day suspension).
Restrictors will be teched by NO-GO Gauges effective 6-1-2014
Intake end: maximum diameter 0.950"
Throttle end: maximum diameter 0.632".
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