General Rules - Honda GX160 Tech Manual

GENERAL RULES

1. Only stock Honda GX160K1 HX2 and HX26* engine and gearbox will be used in this class. All parts will be stock
Honda specifically made for the Honda GX160OK1 HX2. U.S. # GCACK & GCAAK – Canada #GCABT
A. All 160 Honda engines must be updated to the new E2 Style piston and cylinder head.
B. Failure to update = DQ and Minimum 6 month suspension
All stock Honda parts must be used and properly installed with the following exceptions:
The following gaskets (list below) that are coming from Honda are tan and green will be legal to use.
Intake Gasket, Carb Gasket, Side Cover Gasket
A. Governor system may be partially or fully removed with the exception of the steel drive gear on the
crankshaft. This gear must remain intact. If shaft is removed, hole must be plugged. Hole can be taped for thread
or epoxy. No welding.
B. 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 devices inside the air filter or adapter. (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. 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.
C. Stock Honda fuel tank must be removed.
D. Recoil starter must be removed. Pull cup may be cut down for washer. Must use original cup.
E. Exhaust: Stock Honda muffler will be removed. Mounting flange may be cut off of muffler and used as
adapter flange. Any transition from the "D" shape of the exhaust port to round must take place with in the
thickness (0.250" max.) of the flange. This applies to all exhaust systems. No steps or tapers allowed, grind
marks are allowed past 0.250" flange area. No suspension for exhaust flange or pipe infraction just
disqualification. If an after market flange is used, maximum allowable flange thickness will be 0.250
inches. If slip on type flange assembly is used, pipe stub will be a maximum 0.880 inches outside diameter
tubing with a maximum overall length of 1.500" inches. Pipe stub must be inserted into exhaust pipe at
least 0.750 inches and will have minimal exhaust leakage. Muffler to be used will be 4 to 8 hp Briggs &
Stratton, part number 294599 or equal equivalent. Muffler will be internally unaltered except that the round
cup shaped baffle may be welded to the perforated baffle without moving it's original location. Threads
will not be removed from muffler. Exhaust pipe will be a maximum of 1.000" inches outside diameter with
a length of 20.0" to 26.0" including a threaded pipe coupler to welded to the end of the pipe in order to
screw muffler in place so that muffler may be removed for inspection. Pipe must be one piece continuous pipe
from flange or slip nipple to muffler coupler. No sections of pipe welded together (butt welds). Pipe coupler will be
a standard, unaltered, ¾" NP, threaded coupler. Length will be 1.000" inches minimum to 2.250" inches maximum.
There will be no steps or tapers in exhaust pipe or flange assembly. Exhaust pipe length will be measured
by using a small diameter hose inserted though pipe to measure over all length. Flange and coupler will be
included in the overall length when measuring pipe. No coating of any type may be applied to the interior
of any part of the exhaust system. The intent of this rule is to have all of the exhaust pass through the
muffler. All measurements are to be taken with the component pieces in the same position as they were
installed and on the car.
1. All 160 ¼ midget mufflers must be Briggs & Stratton Part # 294599 or equivalent. No drilling
F. Choke butterfly & shaft must be removed. Hole may be filled only with silicone. Old shaft may be cut down.
G. Oil level switch may be disconnected but switch assembly must remain intact in crankcase.
H. Gearbox may be rotated to any desired position.
I. Main jet in carburetor may be a maximum of #82 (0.033 nogo). Silver jets are legal.
J. Off-On ignition switch may be removed, and hole covered. (any material; no welding)
K. All pin measuring gauges are plus tolerance.
holes in the baffles. Inside seam of baffle must be straight edged. (NOTE: Some seams may not
be parallel in baffle) You cannot cut off the threaded flange if it is to be used in Honda. It is OK
to weld a washer or nut on the flange for a place to apply safety wire
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