Single cylinder OHV engines only. Clone or Predator 212.
Stock engine with a maximum displacement of 212cc.
Stock engine with a minimum combustion chamber of 26cc. To be checked with CC nut.
Stock cylinder head is required. No porting or polishing of the Intake/Exhaust runners. No visual alterations may be performed in the runners, bowl area, or around the valve guide. All head gaskets are legal.
Stock crankshaft unaltered, 2.165” maximum stroke.
Unaltered SFI-approved flywheel required.
Any length connecting rod is legal. Billet aluminum is legal.
Stock unaltered piston only (2.766” maximum).
Stock camshaft cores only, ez-spin assembly must remain as stock. Max intake lift on cam .225"-min .215" lift taken at push rod. Max intake lift at the valve (.261" for Hemi/ .236" for Wedge Head) taken on the valve spring retainer with zero lash. Max exhaust lift on the cam .232"-min .222" lift taken at pushrod. Max exhaust lift at the valve (.267" for Hemi/ .243" for Wedge Head) taken on the valve spring retainer with zero lash.
Stock rocker arms unaltered (Non-Hemi 1:1 ratio max, Hemi 1:1.1 ratio max).
Stock lifters unaltered.
Any push rods are legal.
Stock valves and valve size for the make/model of the head. Stainless replacements OK but must remain stock size for that head. Reaming Valve guide to accept stainless valves also permitted.
Valve Spring Installed Height Minimum .815 Maximum Spring Tension of 10.8 at a Height of .850 Max Wire Diameter Of .071”.
Any retainers and keepers legal.
Stock valve cover unaltered (You may install fuel pump port).
Stock side cover unaltered. Pulse fitting OK.
Any ignition coil is legal (wire and boot non-tech item).
Exhaust Requirement: Any Winnie pipe with minimum length tubing of 5.5" and maximum of 6.5" measured from the surface of the gasket where it meets the head to the end of the threads and maximum OD tubing diameter of .750" measured on the straight section of the pipe, with a +/- .010" tolerance. A transition allowance will be given from the top of the flange up the tube .5" for transition from the stated OD tubing diameter. Flange thickness will be limited to .5125". RLV Mini 91 Muffler REQUIRED, no alterations to the muffler. The pipe must not be altered to leak via holes in the side of the pipe or gasket.
Stock appearing clone carburetor measuring a maximum .615 at the Venturi and .751” at the exit (Measured with ‘NO-GO’ gauge plus a roundness check of Venturi. Venturi must be round. No odd shapes. (i.e. egg or ‘D’ shape). Choke may be removed. Green single hole restrictor plate mandatory (.425" max) placed between the carburetor and the insulator adapter. Any attempt to draw air past plate will be disqualified.
Pump gas only with track designating baseline.
Any air filter and/or adapter are legal.
Aftermarket carburetor spacers and insulators are illegal.
Removal of governor and/or governor components is legal (Plugging holes legal).
Removal of oil sensor and/or oil sensor components is legal (Plugging holes legal).