Sugar River Raceway will use the Clone rules called 'International Class Box Stock' in the 2011 WKA tech manual section 711 starting on page TM-93.

Any 6.5 HP Chinese produced Honda Clone engines can be used. All parts must be factory production parts unless otherwise specified in this manual. No machining or alteration of parts is permitted unless specifically noted. All parts are subject to be compared to known stock parts. No reading between the lines. If it's not in the rules it must remain stock. Unless otherwise, stated engines will be teched as raced. Additional rules may be added as WKA moves forward with this program.

711.1 Clutch: Must be a shoe type clutch. Any stamped drum clutch allowed. No machined billet drums allowed. No disc clutches will be allowed.

711.2 Fuel Tank: Must be floor mounted.

711.3 Carburetor: Huayi or Rui*ing only. All stock garb gaskets must be present. Choke assembly must be functioning, cannot be altered and must remain flat. Choke bore must be cast. Venturi 0.615" No-Go. Back carb bore: 0.751" No-Go. Emulsion tube must remain stock. 0.066" No-Go (No-Go cannot pass all of the way through). Main jet: 0.042" No-Go. Low speed idle jet 0.019" No-Go. Throttle shaft 0.115" minimum. Butterfly 0.037" minimum. Butterfly screw must remain stock.

711.4 Fuel Pump: Any pulsed type fuel pump is allowed. Fuel pump must be pulsed from the valve cover. *Any other way to pulse must be approved by the tech official at the race.

711.5 Air Filter: After market air filter adapters are allowed. Maximum length: 1.375". Loss of air filter during a race does not constitute a reason for disqualification.

710.6 Block: Block must remain stock. Maximum bore is 2.685". Stroke is 2.123" plus 0.010" or minus 0.005". No pop up allowed. Mating surfaces of block and cylinder head are non tech items. Surfacing of both to correct for gasket failure and meet cc check is allowed. No welding on the block.

711.7 Cylinder Head: No porting, grinding or modification. Valve seats have two angles; single 45° valve face and single 30° top. Intake seat 0.897" maximum. Exhaust seat 0.862" maximum. Head gasket must be stock configuration. Gasket must be steel; copper or aluminum not allowed. Minimum head gasket thickness 0.008". One or two head gaskets are allowed up to a combined maximum of 0.020".

711.7.1 Combustion Chamber Volume: Minimum volume 26.5cc as measured through the spark plug hole using the LAD tool and with head on the engine.

711.8 Valve Train: Valve train will remain stock. No polishing. No grinding. No alterations. Stock OEM rocker arms only. Stock valve springs only. Maximum wire diameter is .071". Maximum spring pressure is 10.8 lbs. at height of 0.850". Spring retainer measurements - exhaust 0.260" +/- 0.005"; intake 0.0240" +/- 0.005". Intake valve diameter - 0.985" +/- 0.005" with 45° angle. Exhaust valve diameter - 0.948" +/- 0.005" with 45° angle. Lash cap on exhaust valve only. Valve stem seal is optional on intake valve only. Seal lip - 0.027" maximum. Stock lifters are mandatory.

711.9 Connecting Rod: Stock rod only; no modifications.

711.10 Piston and Rings: Stock pistons and rings only.

711.11 Crankshaft: Stock crankshaft only; no modifications. Crankshaft journal is 1.180" maximum and 1.168" minimum.

711.12 Camshaft: Camshaft must meet these specifications. Maximum running lift on exhaust is 0.242" taken on valve spring retainer with zero lash. Maximum running lift on intake is 0.238" taken on the valve spring retainer with zero lash. Intake lift at the push rod -maximum 0.225", minimum 0.215". Exhaust lift at the push rod - maximum 0.232", minimum 0.222". Duration check for intake and exhaust lobes. Intake duration of 218.5 degrees at 0.050" lift, and 85.8 degrees at 0.200" lift. Exhaust duration of 221.5 degrees at 0.050" lift, and 96.5 degrees at 0.200" lift. All checks will allow +2 degrees for wear and gauge variances.

711.13 Flywheel and Ignition: Flywheel and ignition coil must be stock. No alterations, no machining. Timing must be stock with stock flywheel key (0.156" minimum thickness). Plastic fins must remain stock. Weight - Flywheel only - 5 lbs. 4 oz. minimum.

711.14 Header Pipe: Maximum length on header and muffler is 15" and minimum is 10". Header must be single stage maximum 0.750" O.D. and 0.635" I.D.

711.15 Muffler: Muffler must be RLV Mini 91. Box stock, threaded nipple. No grinding. I.D. is 0.685" +/- 0.005". Rear baffle holes maximum I.D. is 0.1285". Inner baffle holes maximum I.D. is 0.0965". Muffler must be screwed on end of header pipe, not welded. Loss of muffler during the race will result in disqualification.

711.16 Starter: Pull starter must be present and remain stock. Engine must be started with pull starter. Pull Starter may be rotated for a better cranking angle.

711.17 Engine Oil Recovery System: Engine oil recovery system (catch can) mandatory.

711.18 Oil Sensor: Oil sensor may be removed.

711.19 Governor: Governor and governor components are non-tech.