2006 IKF Regional Option Class
Super Stock CR125 Moto
Section 850.3 / 306.9.3 / 657
Updated February 16, 2006
 

657 Super Stock CR125 Moto

657.1 Conditions And Definitions Specific To This Class:

657.1.1 This set of rules were developed jointly by IKF Region 11 (NorCal) and Region 6 (Pacific Northwest) with guidance from the IKF Shifter Committee.  They provide engine rules that can be used in either Road Racing or Sprint.

657.1.2 Guidelines offered in these pages are subject to the term "Spirit and Intent" and apply to the technical aspects of this "Stock" sprint shifter kart class. It is expected that all participants will adhere to the spirit and intent of these rules.  These are guidelines for fair and equitable competition.  They are not the basis to "read between the lines" in order to circumvent the intent.

Spirit And Intent:  "If these paragraphs do not say you can, you can't!"

657.1.3 Stock Defined:  All displacements will bear a tolerance that will be defined by specifications deemed as "Factory Stock," in specifications from said manufacturer.  All post event technical inspection will rely on published factory specifications and may be compared to known stock parts.

Neither the OEM engine nor any of its auxiliary components may be modified in any way, unless an exception and / or exclusion is specifically noted within the rules.  This includes the addition, deletion and / or omission of and / or adjustment to parts and / or materials.  Note:  Adjustments to components that are specifically designed for that purpose shall not be construed to be a modification (i.e. Carburetor jets, needles, slides, adjustment screws, spark plugs, exhaust flange spacers, etc.).

657.1.4 OEM Defined: For purposes of defining allowable engine components, OEM will mean parts produced by a particular manufacturer for a particular model.  Where OEM parts are called out for example, you may not use Yamaha parts in a Honda engine, or Honda RS parts in a Honda CR engine. Except where otherwise stated, the year of manufacture is open, provided the parts are commercially available in the U.S. market.

830.3 Super Stock CR125 Moto  (400 lbs.)
 

306.9.3.1 Chassis:  Same as IKF F125 Ltd.
 

306.9.3.2 Bodywork:  Same as IKF F125 Ltd.
 

306.9.3.3 Brakes:  Same as IKF F125 Ltd.
 

306.9.3.4 Tires:  Same as IKF F125 Ltd.
 

657.2 Engine:  Stock 1999 OEM Honda CR125 kit engine.

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657.3 Top End:  Cylinder and cylinder head must be stock 1999 OEM.

657.3.1 Exception(s):  Power valves must be removed and the power valve ports plugged (power valve plugs may be modified to achieve desired fit).  No grinding of the cylinder allowed, all blending must occur in the plugs.  The power value actuator rod hole may be plugged.  OEM power valve covers may be replaced with aftermarket plates.

657.3.2 CCV:  Minimum 11.0 CCV, measured with a L.A.D. tool (part #CCMP).  Head gasket must be stock OEM.  Base gaskets of varying thickness may be utilized to obtain the target 11.0 CCV.  Total base gasket thickness shall be a minimum of 0.010 inches and a maximum of 0.030 inches.

657.3.3:  Cylinder may be honed, but may not be repaired (replated), if damaged.

657.3.4:  Piston, ring, wrist pin and upper rod bearing must be stock OEM.

Exception:  For the purpose of cooling / lubricating the exhaust bridge, up to a maximum of three holes may be drilled (0.0625 inch maximum diameter), in the exhaust side of the piston.

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657.4 Bottom End:  Crank, rod and flywheel assembly, including bearings and seals, must be stock OEM.

Exception:  Sanding / polishing to allow for slip fitting of bearings to crank is permitted.

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657.5 Intake System:

657.5.1 Carburetor:  Box stock PWM or PWK 38mm carburetor.  Bore may not exceed 38.6mm in diameter.  Carburetor bore measurement will be determined at the engine side of the slide.  Bore may not exceed the designated maximum diameter in an area .400" wide measured inboard of the slide.

657.5.2 Fuel Pump:  Pump around fuel recirculation system is allowed.  Single, pulse type pump feed system.  One (1) feed pump only.  Any additional pump must be for evacuation (i.e. pump around system).  No electric or belt driven pumps.  Catch containers and / or alternative plumbing are mandatory, to deal with potential carburetor overflow.

657.5.3 Manifold And Reeds:  Intake manifold and reed assembly must be stock 1999 OEM.  Note: Bending the reed stop is allowed.

Exception:  A stock Honda RS125 5° intake boot (P/N 16220-NF4-900) is allowed; the rubber lobes may be notched or cut flush with the mounting surface, so that it will fit into the stock 1999 OEM reed cage.

657.5.4 Intake Noise Suppression:  Air boxes are required only when local authority mandates.  IKF rule 603 applies.

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657.6 Ignition System:

657.6.1 CDI:  Required Denso part #071000-1410 and coil must be stock 1999 OEM.  Note:  The wires connecting the coil and stator to the CDI may be lengthened or replaced, to facilitate mounting of the CDI unit.  The addition and use of a coil ground cable is recommended. Kill switch, if used, must function only to kill the engine.  The spark plug wire and cap are non-tech items.  Note:  The events technical director may require a competitor to swap CDI boxes, prior to the start of a race event.  Failure to comply will result in disqualification for the day.

657.6.2 The stator and flywheel must be stock 1999 OEM. The left (front) outer steel stator plate may be removed, allowing an estimated + / - 1° of timing change.

657.6.3 The spark plug manufacturer is open, but the plug must be commercially available and measure 18.5mm long by pitch M14 x 1.25.

Exception:  The spark plug washer may be removed to facilitate the use of a cylinder head temperature sensor and the gap of the electrode may be adjusted.

657.6.4 Timing cover is non-tech.

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657.7 Exhaust System:

657.7.1 Pipe:  The required pipe is R.L.V. part #6800 which may not be modified.  Note: Spacers are allowed, between the cylinder and the exhaust flange.

657.7.2 Silencer:  Exhaust silencer body shall be a minimum of 12 inches and a maximum of 14.5 inches in length and at least 3 inches in diameter (minus 5% tubing tolerance).  Silencer core must be perforated for a minimum of 10 inches in exposed length, with 0.125 inch or larger diameter holes, on a 0.1875 inch staggered center pattern.  The silencer core shall be a minimum of 0.875 inches and a maximum of 1.25 inches inside diameter and must be wrapped in fiberglass or steel wool.  The length of the silencer inlet shall not exceed 1.25 inches.  The length of the silencer outlet shall not exceed 1.25 inches for a straight tip and 3.25 inches cord-length for a curved tip.  The rolled edge provision applies.

657.7.3 O-ringed aftermarket exhaust flange allowed (40mm inside diameter plus or minus 0.5mm).  Note:  Removal of carbon build-up from the inside of the exhaust flange will not be deemed to be a modification.

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657.8 Transmission / Clutch:  1999 Honda CR125 kit engine utilizes a 1997 6-speed transmission.  All components must be stock OEM.

Exception:  Finish on gears is non-tech.

Shifter must be a manual mechanical apparatus.  Note:  While air / electric / pneumatic shifters are not allowed, this restriction may be waived to accommodate special driver needs and requires prior written approval.

Use of a sprag axle hub assembly is permitted.

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657.9 Cooling System:  One of the water outlets in the cylinder head may be plugged.  Note: The stock water outlet(s) must remain in the original location, in relation to the exhaust port.  OEM water pumps must be retained.  No axle or external water pumps allowed.  Cooling system may use only water and / or water based coolants.  The size and routing of the cooling hose(s) is open.  Catch containers and / or alternative plumbing is mandatory, to deal with potential radiator overflow.

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657.10 External Modifications:  Cases must be stock OEM.

Exception(s):  Kick-starter assembly may be removed and the hole plugged.  Removal of the kick-starter hump is allowed.  The case may be clearanced to accept a larger front drive gear.

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657.11 Other:  Studs, bolts and washers are non-tech.  Accessory mounting brackets and locations are open.  Chain guards are required (steel is recommended).

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657.12 Legacy Motors are allowed in competition, during the 2006 season only.  Competitor must declare that they are using a "Legacy Motor", DURING or PRIOR to pre-race tech inspection.  A weight penalty may be assessed, to offset any small gain in performance derived through the use of a modified crankcase.

Legacy motors are defined as engines with material added or removed from inside the crankcase.  Other than machining / modifications within the crankcase and reed throat areas, a legacy motor must comply with the 2006 Super Stock CR125 rules as written.