RULES SUBJECT TO CHANGE WITHOUT NOTICE
Block & Side Cover Repair/ModificationWelding of epoxy repair permitted to the block and side cover. Repair may not be a functional modification (performance enhancing). Decking of the block is permitted. No pop-up of the piston is allowed.
Fuel87 octane pump gas only.Floor Mounted gas tanks are required. OEM tank must be removed.Any pulse type fuel pump permitted and can be pulsed from the crankcase, side cover, or valve cover.
CarburetorStock Huayi or Ruixing type carb only.Choke assembly must be in place and functional.Choke lever must be stock. Drilling holes to mount choke lever is prohibited.Venturi - .608" Must-Go, .615" No-Go.Throttle Bore - .751" No-Go.Throttle Shaft - .115" minimum thicknessButterfly - .037" minimum thickness, butterfly screw minimum length .305"Jets - Main jet and low-speed idle jet are non-techFilter Adapter - Max 1.375" height. Grinding or modifying spacer between filter adapter and carburetor is prohibited.Emulsion Tube - through hole maximum ID of .066" No-Go. Minimum length is 1.092" and must have 20 holes on top; hole diameter must be .036" No-Go. Bottom holes can be either 2 or 4 holes. Minimum diameter is .154".Phenolic Insulator - Must be run between carburetor and block. Plate hole and finish of plate are non-tech. Fuel Bleed off slot must be unaltered. Thickness must be maintained at .257" minimum. Plate must be flat and maintain consistent thickness at all points.
PistonMust be of three ring design. Minimum weight of 145 grams with oil expander ring and two rail rings installed. Piston length is 1.935" max, 1.910" minimum, .580" max top of wristpin hole to top of piston as measured with a dial caliper.Standard bore is 2.685", maximum overbore allowed is 2.700".Piston is not allowed to be any higher than the deck of the block at TDC. No flat top piston allowed. must be dished-OEM w/no modifications.Aftermarket pistons and/or sizes up to .010" over are permitted.Machining of piston is prohibited.Piston RingsMandatory that all three rings to be intact and functional.Top ring must be chrome faced.No alterations of rings are permitted. Ring Tension RequirementsTop two rings must support themselves. in the cylinder when removed from piston. They cannot fall through the cylinder.Bottom ting is a non-tech item regarding tension. Bottom expander ring & two rail rings, when mounted on piston and rod in place should support piston in cylinder when inserted upside-down.Ring Tension Inspection ProcedureTop two rings must support themselves without assistance in cylinder.Each of the top rings should be placed, indivdually, approx. one inch down in the cylinder.Square ring with piston turned upside down. If ring supports itself, it is legal.
CrankshaftStandard OEM item with stock stroke of 2.126" (+/- .007")No alterations permittedJournal diameter must be between 1.168' - 1.180"If needed to prove lack of modification, crankshafts minimum weight would be over 1700 grams.
Ignition CoilMust be OEM for all classesTiming is non-tech
FlywheelFlywheel key may be altered and is non-tech; key is not required to be installed.Flywheels must have a minimum weight of 3.3 pounds.Modifications or removal of fins is prohibited.
Cylinder HeadOnly JT 4-Bolt heads and TG-1 heads will be allowed.Valve SeatsValve seats can have up to three angles as cut by the manufacturer:60-degrees bottom relief45-degrees top relief30-degrees top angle reliefPorting, grinding or matching to the ports or combustion chamber is prohibitedTop of valve cannot be below floor of combustion chamber (cannot sink the valves)No angle milling of head. Measurement taken from gasket surface: depth check to combustion chamber floor cannot vary more than .005" in any directionMinimum Combustion Chamber VolumeMinimum combustion chamber volume when mounted on engine at TDC is 26.5 cc's. This is to be done after the event and when the engine has cooled down to a reasonable temperature. Head DimensionsMax head thickness: 2.640" as measured from the valve breather mounting surface to in-between the valve seats and the combustion chamber. Head thickness from the valve breather mating surface to in-between the valve guide is 1.150" max.Port Depth: measured from the top of the valve seat to the port floor; Intake .880" max, Exhaust .830" maxValve bowl height gauge is the preferred measurement tool.Intake/Exhaust SeatsIntake seat: .899"Exhaust seat: .862" max
Valve TrainValvesSteel or stainless steel valves with 45 degree angle only and no lightening or polishing. Polishing or sandblasting of valve stem up to port entrance is allowed; however, polishing of whole valve is prohibited. Cannot be visible above the valve guide.Valve DimensionsIntake valve OD: .975" MinimumExhaust valve OD: .937" MinimumIntake valve length: 2.525" MaximumExhaust valve length: 2.555" MaximumMinimum valve weight: 21 gramsRocker Arms1:1 Ratio rocker arms onlyRocker arms must be steel and are subject to magnetic test.Rocker arms are allowed to be ground on valve stem location only, or on bottom of rocker arm to allow running lift to be compliant. Grinding on the sides of the rocker arm is prohibited. No minimum thickness checks.Valve SpringsMaximum Coil Diameter: .071"Number of Coils: 4Spring shims are allowed, no thickness check and must maintain .815" height check including shimsSprings must be made of a magnetic materialInstall height .815"; check with must go gauge .815" with retainer in place. Gauge must go in both directions with retainers in place as raced.Lash caps on exhaust valve only. Intake retainer must retain stock appearance - no length or thickness check. Material must be magneticUpper seals optional, seals may be used on both intake and exhaustSpring Coil CheckUsing the Spring Coil Check with a .250" ground tool steel as No-Go gauge.Weight CheckUsing the Weight Check to check tension. Maximum Tension: 10.8lbs @ height of .850" and 18lbs @ height of .650"PushrodLength: 5.275" + .010" MaximumMust be of 3-piece designMinimum weight: 9 gramsLiftersLength: 1.350" - 1.390"Oustide Diameter: .935" maximumMinimum Weight: 18 grams
CamshaftStock appearing camshaft cores only with the ez-spin assembly unaltered and in stock condition is mandatory.Cam lobe base circle diameter min/max is .860" - .875"Duration taken from pushrod. Intake duration of 221 degrees at.050" lift and 88 degrees at .200" lift. Exhaust duration of 224 degrees at .050" lift and 99 degrees at .200" lift. Camshaft tolerances:+2 degrees with no minimum duration checkIntake lift at pushrod is .215"-.225".Exhaust lift at pushrod is .222"-.232".Intake lift at retainer is .238" maxExhaust lift at retainer is .242" maxLift will be checked as raced.
Gaskets & SealersGaskets must be OEM configuration and are non-tech and seal may be applied unless otherwise specified. No sealers allowed on intake or carburetor side!Crankcase gaskets: Maximum two gaskets and/or sealer allowedNon-performance enhancing marking, "engraving", sanding or other minor modifications to gasket mating surfaces to improve/enhance sealing capabilities is allowed.
BearingsCrankshaft bearings shall be of metallic (magnetic steel) construction and be of conventional design and stock appearing and the same dimensions as the OEM bearings. This includes inner and outer races as well as the balls and rollers. No other materials allowed.
Coatings & PolishingCoating, tumbling, and/or polishing of internal parts, including carburetor and head, is prohibited.
Crankshaft BreathersCrankcase breathers are to be routed internally through the valve cover as orginally intended in OEM configuration. No additional breathers allowed.
RodBillet rods are acceptedHoning is allowed but must maintain factory defined edge.Oil hole size is non-techRod DimensionsRod length:2.350"-2.375"Rod Minimum Weight: 133 grams with cap and boltsWrist Pin DimensionsWrist pin inside diameter: .555" maximumWrist pin outside diameter: .707" +/- .005"Wrist pin length: 2.100"-2.200"
Restrictor PlatesModifications to the restritor plate is prohibited. The anodizing shall not be removed around the holes in the plate. The plate must be flat. Holes must be as produced, with no rounding of the edges.Avalible restrictor plates, checked with the blade-type No-Go gauge:Blue: .550"Purple: .500"Green: .425"Red: .375"
For Restrictor Plate Classes Only RLV Mini 91 Silencer RequirementsPart #4117 Overall Length 5.470" minimum +/- .005" - 5.600" Maximum +/-.005"Threaded nipple .685" maximum ID (ID as MFG. No grinding, reaming, or polishing allowed.)Rear Baffle Holes .1285" maximumInner Baffle Holes .0965" maximumSilencer must be utilized as produced, with no modifications or alterations permitted. Strap or brace required to silencer for support, and to insure silencer does not turn or unscrew.
ANY KART THAT IS ON THE LEAD LAP IS ELIGIBLE TO CLAIM THE WINNERS MOTOR. YOU MUST RACE TWO WEEKS PRIOR TO BE ABLE TO CLAIM
YOU MUST PULL IN TECH AREA ACROSS SCALES, GIVE YOUR MONEY TO THE SCALE PERSON. THIS MUST BE DONE BEFORE THE NEXT FEATURE RACE IS COMPLETED. (DO NOT WAIT UNTIL THE RACES ARE OVER) IF YOU ARE BLACK FLAGGED DURING THE RACE, YOU ARE NOT ELIGIBLE TO CLAIM. YOU CAN ONLY BUY 2 MOTORS PER RACE SEASON. IF THE PERSON BEING CLAIMED DECIDES TO SWAP MOTORS AND THE ONE DOING THE CLAIMING REFUSES TO SWAP, THEN THEY LOSE THEIR POINTS AND PAY FOR THE NIGHT. IF YOU REFUSE CLAIM TWICE, YOU ARE DONE IN THE CLASS. THESE ARE THE RULES FOR THE CLONE CLASSES, IF YOU DON'T LIKE THE CLAIM RULE DON'T RACE IN THE CLASS.
NO OTHER ALTERATIONS TO OR FROM STOCK COMPONENTS ARE ALLOWED.
IF YOU ARE CAUGHT CHEATING IN THE CLASS YOU ARE DONE IN THE CLASS.
EACH CLASS WINNER WILL PULL A CHIP THAT WILL TELL WHAT ITEM WILL BE TECHED.