Honda GX 120 Tech Manual page 4

TECH PROCEDURE
Modifications or machining of any parts in order to bring them to stated minimum or maximum specs (blueprinting) is not legal.
1. External visual check of engine for required components: Pipe and muffler, shrouds and sheet metal, oil level sensor
(this can be partially observed from outside).
NOTES:
A. . Factory air cleaner must be removed. Any air filter may be attached to the outside of air filter adapter.
Outer wear style or equivalent can be used over carburetor only with no adapter. The approved air filter adapter
may be run with or without an air filter. Any air filter may be used with adapter as long as there are no
device(s) may be used inside the air filter or adapter that will alter the airflow into the carburetor (I.E. Springs
not allowed) Hose from valve cover must go into a catch can. (We are using "outerwear" to define a style not
brand name).
1. Air cleaner adapter will be maximum ID 2.250"and a maximum of 1.375" long in length, flange
thickness 0.375" max. flange ID 1.000" minimum hole size straight walled, flat bottomed and parallel with
carburetor using existing air cleaner mount holes.
2. The use of air filters during qualifying at asphalt and dirt events is illegal. The Senior Tech. Official
reserves the right to allow filters at any event that it's deemed necessary.
B. Any type throttle linkage may be utilized. Carburetor will be unaltered with the exception of the black plastic
piece on upper end of throttle shaft, this is the only part in the carburetor that can be altered.
C. Rear mounting brackets for Honda fuel tank may be removed.
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
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 air flow 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.
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