All Clone classes in WKA West regional series will follow these specifications:
JUNIOR 1 CLONE
Age 7-12. Weight 255 Lbs. Tires 4.5 YLC. Will run .500 purple intake restrictor.
JUNIOR 2 CLONE
Age 12-15. Weight 320 Lbs. Tires 4.5 front / 6.0 rear YLC. Will run .550 blue intake restrictor.
Age 15 and up. Weight 360 Lbs. Tires 4.5 front / 6.0 rear YLC. No restrictor
SENIOR SUMO CLONE
Age 15 and up. Weight 400 Lbs. Tires 4.5 front / 6.0 rear YLC. No restrictor
711 CLONE CLASS ENGINES
Section 711 describe the specifications for clone class engines. These are 6.5 horsepower "Clone"
Engines only. All parts must be factory production parts unless otherwise specified in this manual. No
Machining or alteration of parts permitted unless specifically noted. All parts are subject to be compared to known stock parts + or - .005". No reading between the lines. If it is not in the rules, it must remain stock. Additional rules may be added at any time as WKA West moves forward with this program
UNLESS OTHERWISE STATED ENGINE WILL BE TECHED AS RACED.
All classes must run a shoe type clutch. Drum may be stamped or billet steel. No cooling
Fins may be either machined into drum or added on. Disc clutches are not allowed.
711.2 FUEL TANK
Must be floor mounted
Carburetor requirements: Huayi OR RUI*ING model carb only. Carb to intake sealer is
gasket only no other sealer allowed. Choke must be as supplied from factory, but may
be fixed to stay in open position (Choke area must remain as cast). Venturi .615” NO-GO. Venturi maybe machined to spec, no polishing permitted and all transitions must remain stock in and out of venturi. Rear carb bore .751” NO-GO. Carb bore at rear of carb .750” maximum depth (This measurement is taken from the flat surface on the rear of the carb down to the circular ridge at venturi edge). Main fuel jet .042” NO-GO. Low speed idle jet is a Non Tech item. Stock emulsion tube must be used and unaltered, .066’ max ID (no pass through). Side holes in E-Tube 4 holes in bottom section and 20 holes in top section max. Minimum E-Tube length 1.092”. Side holes in e-tube diameter .036” no go. Throttle shaft - .115” minimum. Stop arm of throttle shaft maybe filed to adjust for butterfly position. Butterfly - .037” minimum. Aftermarket air filter adapter allowed (max length of 1.375). Black Phenolic spacer must be flat across entire gasket mating surface with a minimum thichness on gasket surface of .265”. Deburring of inlet track allowed to remove flashing . Any attempt of inducting air into the intake port other than through the carburetor bore is not allowed. Surface finish of phenolic spacer inlet track, non tech..
711.4 FUEL PUMP
Any pulse type pump is allowed. Fuel pump must be pulsed from the valve cover.
711.5 AIR FILTER
Aftermarket air filter ok, aftermarket air filter adapter allowed (max length of 1.375). Loss of air filter during a race does not
constitute a reason for disqualification
Block must remain stock, Maximum bore is 2.685. No piston pops up allowed. Mating surfaces of block is
Non tech. Surfacing to correct gasket failure and meet cc check is allowed. Oil drain hole between lifters .251” no go. Any type side cover fastener and lock washer permitted, must be original size, sealer permitted. No welding on block
711.7 CYLINDER HEAD
Cylinder Head Requirements: Must be OEM casting only. Porting and / or grinding are not permitted. Valve seats may have up to three angles, 45 degrees valve face and 30 degrees top relief and 60 degree bottom relief. Intake seat maximum ID .897”, Exhaust seat maximum ID .862”. Outside face of valve may not be below floor of combustion chamber (i.e. don’t sink the valves). Stock head bolts only, must have four. Head gasket/s maybe after market, must be of stock configuration, gasket thickness is a non tech item, sealer allowed to insure proper seal. Depth check between the valves, front to back and side to side may not vary by more than .005” max. No copper or aluminum gaskets allowed. Any stock configuration exhaust gasket allowed, sealer permitted, Header may also be run without gasket, sealer only. Allen head bolts permitted on Header to head.
711.7.1 COMBUSTION CHAMBER VOLUME
Minimum volume 26.5cc as measured through spark plug hole using the LAD tool with head on
the engine. See Section 504 for instructions how to use the LAD tool to check cylinder head volume.
711.8 VALVE TRAIN
Valve Train: Stock valve cover only with any stock configuration gasket, sealer allowed.
Factory stock rocker arms 1:1 ratio and push rods only. Surface finish of contact area of rocker arm to valve
stem , non tech, to adjust for proper lift running lift. Stock steel/stainless nitrate coated valves only 45 degree angle only both
valves with a minimum weight of 21 grams each valve, Intake valve Max OD .982” +/- .005” and Exhaust valve Max OD
.945” +/- .005”, no modifications allowed. Single valve springs only. (Installed Height for valve
springs .815”, must be checked by using the .815” spring must go gauge with retainer seal
and shims in place on intake an exhaust valve if used.) Shims may be used to achieve .815” Installed height, maximum thickness of shims used .045”, any combination of valve seal and spring shims allowed. Prescribed check procedure as follows – Remove valve spring, reinstall spring retainer and shims, insert .815” must go gauge in spring location. Gauge must go in both locations Intake and Exhaust with any allowed retainers and shims in place, as raced, during check procedure. Max wire diameter on spring wire is .071” with a maximum tension of 10.8 lbs. at a height of .850”, and a maximum tension of 18 lbs at .650”. Each spring is to be checked using a .750”height by .800”width plate gauge and a .250” (square) no-go gauge to check thecenter spacing of the spring coils while inserted in the plate gauge. Prescribed checkprocedure as follows – Insert the spring in the .750” X .800” plate gauge (spring must be centered in plate gauge and must fit inside of gauge with the ends of the spring wires perpendicular to the plate ). Once inserted in the plate gauge take the .250” no-go gage and check the center coil spacing on both sides. The .250” no-go gauge must be parallel
to the spring wire and perpendicular to the center of the spring when checking. The .250” no-go must pass check on at least one side of the spring. This check is to be performed after the 10.8/lb , 18/lb check, and .071 max wire diameter check have been performed.
Ends of the valve springs may be sanded to help meet spring checks. Lash cap on exhaust valve only. Valve stem seal allowed on Intake and Exhaust valve. Minimum thickness of Intake retainer .225” , Exhaust retainer .245”. BS lifters only, no modifications allowed. Over-all length of push rod 5.285” max. Weight check lifters 18 grams min and push rods 9 grams min.
711.9 CONNECTING ROD
Stock CAST rod and new stock performance CAST rod allowed. Length from top of journal to bottom of wrist pin hole 2.375 max. and 2.350 Min. Honing of journal end and wrist pin hole permitted. Surfaces to remain flat.
Oil hole size : .173 no go
711.10 PISTON AND RINGS
Piston and Rings: Piston must be unaltered Box Stock only. Overall piston length 1.935” max, 1.920” min and from top of wrist pin to top of piston .580” max. Arrow on top of piston must be pointed toward valves/lifters. Overall length wrist pin 2.100” min, inside diameter .550” max.
Top ring and middle ring .115” max width, .060” max thickness.) Filing of ring end gaps permitted including oil
expander, max end gap .040”(top 2 rings only). Lapping of rings permitted for proper seal. Piston ring must be in one
piece(unbroken) when presented for tech. Piston rings must be self supporting in cylinder bore and concentric to
cylinder bore. Oil ring assembly must be self supporting in cylinder bore when checked installed on piston
with connecting rod attached.
Stock crankshaft only;no modifications. Crankshaft journal is 1.180" maximum and 1.168" minimum.
Stroke is 2.123" plus 0.010" or minus 0.010".
Camshaft must meet these specifications. Maximum running lift on exhaust is 0.242" taken on valve
spring retainer at zero lash. Maximum running lift on intake is 0.238" taken on valve spring retainer with zero lash. Intake lift at pushrod - maximum - 0.225", minimum 0.215. Exhaust lift at pushrod – maximum 0.232", minimum 0.222. Duration check for intake and exhaust lobes. Intake duration of 218.5 degrees at 0.050" lift / 85.5 degrees at 0.200 lift. Exhaust duration of 221.5 degrees at 0.050" lift / 96.5 degrees at 0.200" lift (all checks will allow +2 degrees for wear and gauge and wheel variances.
711.13 FLYWHEEL AND IGNITION
Ignition coil must be stock, but ignition timing is non tech. Coil may be shimmed to align with magnet.
Flywheel can be billet steel, or stock cast wheel @ 5 lbs 3 ozs, Plastic fins must remain stock, ARC #6619 billet aluminum and PVL cast aluminum wheels also legal. Flywheels may not be modified. Flywheel key is non tech.
711.14 HEADER PIPE
Any single stage, one-piece header made from .750” OD / .635" ID steel tubing, with the RLV Mini B-91 Silencer installed at the end of pipe.The entire exhaust pipe including the muffler is 15” max length and 10” min length. Exhaust Pipe must be double nutted or safety wired.
Sealer may be used to assist gasket seal. Header may also be run without gasket, sealer only
RLV Mini 91 Silencer Requirements: Part #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" maximum, inner baffle holes .0965" maximum. Silencer must be utilized as produced, with no modifications or alterations permitted. All exhaust must exit rear of muffler, muffler may not be run loose causing exhaust to leak at threads.Strap or brace required to silencer for support, and to insure silencer does not turn and unscrew.
711.16 PULL STARTER/FLYWHEEL SHROUD (Blower Housing)
Tape may be used to control engine temperature on these parts only. Pull starter must be present and remain stock. Pull starter may be rotated for better cranking angle.
711.17 ENGINE OIL RECOVERY SYSTEM, FILL AND DRAIN PLUG
Hose ran from valve cover breather hole, must be run to a catch can. Oil fill and drain plugs must be
safety wired along with bottom two side cover bolts.
711.18 OIL SENSOR
Oil sensor may be removed.
Governer and governer components are non tech.
11.20 SIDE COVER GASKETS
2 gaskets maximum.
711.21 AFTER MARKET COATINGS
No aftermarket coatings of any kind are allowed except on blower housing shroud.
711.21 SHEET METAL
All sheet metal must be used as supplied with engine.
Fuel for all clone classes will be pump gas
Claimed motor will consist of complete motor less flywheel as supplied from BSP. Amount of claim is $300 cash only and could be
subject to change with the market value, CLAIM CONSENT forms must be filled out and signed with entry form in order to recieve series points.
CLAIM form will be filled out, signed and put in a sealed envolope along with $300 cash by RACER, then given to Tech Official prior to start of Main Event
After checkerd flag, envelopes will be opened and handed out acordingly. Claimer must be a DRIVER in same class, and race that day, A participant may only claim one time per calender year in each club program or regional series. Claimed engine will be subject to TECH done on that day, If CLAIMED motor is found to be ILLEGAL or DAMAGED in race, the CLAIMER will be given option to proceed with or withdraw thier claim, If more than one participant claims the same engine, the participant with lowest point total for the event is awarded the claim. If a participant fails/refuses to surrender the claimed engine, the participant will forfeit all points and will be ineligible to compete in remainder of series