Tacmedic83
New member
Based on these rules how would you build this engine?
Start with an HF Predator and get creative, remember, it's green plate and will use an EVause carb and weenie pipe. What cam would you use and what other go fast goodies or tricks to get most power within these rules. I do not want to cheat as, well, I can't stand a cheater but also tech is very tight!
JR1: 6-10 years old
260LB WEIGHT RULE
Semi-Skilled kid class (Cage kart only)
*
Single cylinder OHV engines only (i.e. Clone).
Stock engine with a maximum displacement of 212cc.
Stock engine with a minimum combustion chamber of 24.58cc (To be checked through the spark plug hole with syringe).
Stock un-ported cylinder head is required (All head gaskets are legal).
Stock crankshaft unaltered (Aftermarket flywheel required i.e. ARC #6625).
Any*length connecting rod is legal.* Billet aluminum is legal.
Stock unaltered piston only (2.756” maximum).* *Head and piston must be of the same make and model (i.e. Hemi head to flat top Hemi piston).
CAMSHAFT REQUIREMENTS:* STOCK CAMSHAFT CORES ONLY, EZ-SPIN ASSEMBLY MUST REMAIN AS STOCK.* CAM LOBE BASE CIRCLE DIAMETER .865" -.005"/+.010"*MAX INTAKE LIFT ON CAM.225" - MIN.215" LIFT TAKEN AT THE PUSH ROD.* MAX INTAKE LIFT AT THE VALVE .261" TAKEN ON THE VALVE SPRING RETAINER WITH ZERO LASH.* MAX EXHAUST LIFT ON THE .232" - MIN.222" LIFT TAKEN AT THE PUSHROD.* MAX EXHAUST LIFT A THE VALVE .266" TAKEN ON VALVE SPRING RETAINER WITH ZERO LASH. (TO ACHIEVE ZERO VALVE LASH FOR CHECKING RUNNING LIFT, PRELOAD DIAL INDICATOR BY .001”)).
Stock rocker arms unaltered (1:1 ratio max). Hemi stock rockers are 1:11
Stock lifters unaltered.
Any push rod is legal.
Any valves stock size for that engine make and model are legal.
Valve Spring Installed Height Minimum .815 Maximum Spring Tension of 10.8 At a Height of .850 (Max Wire Diameter of .071”)
* Any retainer and keeper is legal.
Stock valve cover unaltered (You may install fuel pump port).
Stock side cover unaltered.
Any ignition coil is legal (wire and boot non-tech item).
ARC single hole GREEN carburetor restrictor plate required unaltered.
Exhaust:* RappFab "Winnie pipe" turned up (EFR-RF-BS-CP-N) or ARC “Winnie pipe” (DJ-1138B) with RLV Mini 91 Muffler REQUIRED, no alterations.
Shoe Clutch only (Any make).
Stock appearing clone carburetor measuring a maximum .615 at the butterfly and .751” at the exit (Measured with ‘NO-GO’ gauge), any gasoline is legal including racing gas.* No alcohol over 10%.* Choke may be removed.
Any air filter and/or adapter is legal.
Aftermarket Carburetor spacers and insulators are illegal.
Fuel tank must be relocated and a pulse fuel pump installed.*
Vacuum may be accessed from anywhere on the valve cover or crankcase.
Stock pull start only unaltered.
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).
No wedge bodies.*
3 piece champ kart bodies only
Start with an HF Predator and get creative, remember, it's green plate and will use an EVause carb and weenie pipe. What cam would you use and what other go fast goodies or tricks to get most power within these rules. I do not want to cheat as, well, I can't stand a cheater but also tech is very tight!
JR1: 6-10 years old
260LB WEIGHT RULE
Semi-Skilled kid class (Cage kart only)
*
Single cylinder OHV engines only (i.e. Clone).
Stock engine with a maximum displacement of 212cc.
Stock engine with a minimum combustion chamber of 24.58cc (To be checked through the spark plug hole with syringe).
Stock un-ported cylinder head is required (All head gaskets are legal).
Stock crankshaft unaltered (Aftermarket flywheel required i.e. ARC #6625).
Any*length connecting rod is legal.* Billet aluminum is legal.
Stock unaltered piston only (2.756” maximum).* *Head and piston must be of the same make and model (i.e. Hemi head to flat top Hemi piston).
CAMSHAFT REQUIREMENTS:* STOCK CAMSHAFT CORES ONLY, EZ-SPIN ASSEMBLY MUST REMAIN AS STOCK.* CAM LOBE BASE CIRCLE DIAMETER .865" -.005"/+.010"*MAX INTAKE LIFT ON CAM.225" - MIN.215" LIFT TAKEN AT THE PUSH ROD.* MAX INTAKE LIFT AT THE VALVE .261" TAKEN ON THE VALVE SPRING RETAINER WITH ZERO LASH.* MAX EXHAUST LIFT ON THE .232" - MIN.222" LIFT TAKEN AT THE PUSHROD.* MAX EXHAUST LIFT A THE VALVE .266" TAKEN ON VALVE SPRING RETAINER WITH ZERO LASH. (TO ACHIEVE ZERO VALVE LASH FOR CHECKING RUNNING LIFT, PRELOAD DIAL INDICATOR BY .001”)).
Stock rocker arms unaltered (1:1 ratio max). Hemi stock rockers are 1:11
Stock lifters unaltered.
Any push rod is legal.
Any valves stock size for that engine make and model are legal.
Valve Spring Installed Height Minimum .815 Maximum Spring Tension of 10.8 At a Height of .850 (Max Wire Diameter of .071”)
* Any retainer and keeper is legal.
Stock valve cover unaltered (You may install fuel pump port).
Stock side cover unaltered.
Any ignition coil is legal (wire and boot non-tech item).
ARC single hole GREEN carburetor restrictor plate required unaltered.
Exhaust:* RappFab "Winnie pipe" turned up (EFR-RF-BS-CP-N) or ARC “Winnie pipe” (DJ-1138B) with RLV Mini 91 Muffler REQUIRED, no alterations.
Shoe Clutch only (Any make).
Stock appearing clone carburetor measuring a maximum .615 at the butterfly and .751” at the exit (Measured with ‘NO-GO’ gauge), any gasoline is legal including racing gas.* No alcohol over 10%.* Choke may be removed.
Any air filter and/or adapter is legal.
Aftermarket Carburetor spacers and insulators are illegal.
Fuel tank must be relocated and a pulse fuel pump installed.*
Vacuum may be accessed from anywhere on the valve cover or crankcase.
Stock pull start only unaltered.
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).
No wedge bodies.*
3 piece champ kart bodies only