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Restricted & Jr. Box Stock Rules

BOX STOCK CLASS
275lbs

Age limit:
a. Restrictor Box Stock Outlaws : 6 to 8 (All exceptions must be approved by promoter.)(.425 restrictor plate)
b. Box Stock Outlaws : 8 to 13 (All exceptions must be approved by promoter)

NOTARIZED MINOR RELEASE IS MANDATORY. A new release for every race season.
In addition, when parent or guardian is not present at race event, a DESIGNATED GUARDIAN form is mandatory. One for each race.
Minor must be accompanied by an adult at all times while in the pit area. Parent/Guardian is responsible for the actions of their minor child. Bike riding and playing in the pit area is prohibited.
Any parent/guardian or pit crew member observed verbally or physically abusing other drivers will result in a fine and/or loss of points for their driver. NO EXCEPTIONS!

STOCK BRIGGS & STRATTON ENGINE RULES:

Technical Inspection Procedure
Engine No's 130202, 130232, 131232, 132232,133230,133232,135230 & 135232 UNLESS OTHERWISE SPECIFIED. ALL PARTS ARE TO BE STOCK AND UNALTERED.
PARTS MAY BE TECHED AGAINST A KNOWN STOCK PART. DO NOT ASSUME ANY ITEM IS LEGAL BECAUSE SPECIFIC REFERENCE IS NOT MADE IN THE "TECH MANUAL" ASK YOUR TECH OFFICIAL.

   1.  Any after market fastener may be used except for rod bolts, head bolts and carb butterfly. Repairing of stripped bolt holes allowed but stock size and location must be retained. Gasket surfaces may be machined, stock angles must be maintained. Excessive removal of material not allowed. Aftermarket gaskets and diagphrams may be used as long as they remain the same dimensions.

   2.  Engine may be run with or without a air filter. If a filter is used it must be used with a legal adapter. Filter may not act as a ram tube. Sides of filter may not be of less dense material that top. May use two gaskets between carb. and air filter adapter. Silicon or O-ring permitted.

  3.  Exhaust pipe may not protrude into block. Holes other than for theermocouple not permitted.

  4.  All shrouds and coil air vane must be used. Flywheel screen must be on flywheel or shroud. Cutting shroud for tire clearance allowed.

  5.  Recoil may or may not be used. Stock ratchet, starter cup or after market starter nut allowed. Ratchet end of crank may be removed.

  6.  Briggs magnetron ignition only. Coil 2,000 ohms minimum, 5,000 ohms maximum. Any plug connector allowed but must be included in ohms check. Silicone may be used on low tension wires.

  7.  Tank may have one or two gaskets installed. Clearancing for tire, repairing and bracing allowed. Splash Shield, may be used.

  8. CARB
    a. Flange may use one or two gaskets. With the .696 No-Go in the back side of the carb, it cannot hit the butterfly when open. No sealers anywhere other than end plug, pickup tube and as sealer between air filter adapter and carb.
    b. Swirl may be removed.
    c. Bore .695" maximum inside dimension includes the entire length of the carburetor bore. Metering hole protrusions not permitted. Counterbore .726" no-go only.
    d. Throttle shaft .086" minimum at back, .040" at front. Stock butterfly screw mandatory. Minimum length of screw is .322". New Torx screw may be used. No modification to butterfly. Where butterfly mates with throttle shaft, it shall have a minimum dimension of .058" and of .101" at back of ramp thickest point. Felt or foam washer must be on carb shaft under lever.
    e. Choke may be removed and holes plugged. Plugging material may not enter carb bore. If choke is installed it must be stock. New style carbs from factory have no choke holes.
    f. Jet may have remote tuner. Jet must be installed as from factory. Hole size in jet non-tech. No recessing of hole permitted from back side. No funneling or oblonging of hole permitted.
    g. Idle hole .028" no-go. High speed hole .062" no-go. Straight round holes only. No tapered or oblong holes allowed.
    h. Pickup tube screen optional and non-tech. I.D. .066" no-go for short tube steel winding. No-Go cannot pass completely through tube when checked from either end.
    i. Maximum air horn inlet 1.011". No machining allowed.
    j. Aftermarket device to repair broken ear on carb permitted.

  9.  Aftermarket head gaskets of same size and material permitted. Minimum thickness .043" checked halfway between holes. No sealers or coatings.

   10.  Head must check .011", .408", .300" minimum; .315 maximum. Soft carbon may be wiped with rag before checking. Hard carbon may not be removed. Only headbolt mating surface and gasket surface may be machined. Glass beading or sanding for carbon removal only. Head bolt holes .348" no-go.

   11.  Maximum piston pop out at wrist pin centerline .015". Deck must remain above valve seat.

   12.  Maximum bore 2.607". Inspect deck for reworking of eyebrow area.

   13.  Stroke 2.4270" to 2.4470"

   14.  30 degree, one angle intake valve, minimum diameter 1.115". 45 degree, one angle exhaust valve, minimum diameter .990". Minimum edge margin .025". IC block must run cool bore exhaust valve, spring and retainer.

   15.  May use Intake or Exhaust spring on intake valve. Must use Exhaust spring on exhaust. Maximum length 1.500". Maximum wire diameter .092. Minimum inside diameter .625".

   16.  30 degree, on angle, valve seat diameter no-go. 1.005" intake. 45 degree, one angle, .880" exhaust. Inlet port .880" no-go. Exhaust outlet 1.005" no-go. No-go check to be made at intake port inlet and exhaust port outlet. Port area surface and finish are non-tech, but there can be no addition of any material. Valve seat inserts must remain unaltered.

   17.  Any upper spring retainer allowed. .058" maximum thick-ness. Upper part of valve spring chamber may be machined to prevent coil bind.

   18.  Stacking of stock valve guides and one-piece guided allowed, installed as factory intended.

   19.  Flywheel may not be altered in any way. No broken fins or painting allowed. Minimum flywheel weight 5lbs. 12oz.

  20.  CAM PROFILE
Zero degree wheel with position piston stop.
Exhaust Intake
.050----------(38-33 BBDC) .050------------(7 DTDC - 0 TDC)
.100---------- (21 - 16 BBDC) .100--------------- (10 - 7 ATDC)
.150---(2 BBDC - 3 ABDC) .150---------------(29 - 36 ATDC)
.200 ----------(21 - 31ABDC) .200 --------------(55 - 64 ATDC)
Max.------------------- (.233") max.------------------------ (.233")
.200-----------(76 - 65 BTDC) .200---------------(43 - 33 BBDC)
.150 ---------(48 - 40 BTDC) .150-------------- (13 - 6 ABDC)
.100 ----------(28 - 21 BTDC) .100 -------------- (6 - 13 ABDC)
.050------------ (10 - 4 BTDC) .050 ---------------(23 - 31 ABDC)
E-Z Start------ (45 - 60 ABDC) E-Z Lift---------(.013" minimum)
E-Z Lift----- (.019" maximum) E-Z Duration (30 degree minimum at .001" drop

Note: All cam profile readings must be taken with zero valve lash. When checking cam profile, rotate engine in the direction it runs only. (Valves should have no clearance and no spring tension when checked.)

   21.  Multiple side plate gaskets allowed. Center punching of gasket surface allowed.

   22.  Cam has no visual check on the lifter surface. Cam block boss O.D. and finish are non-tech.

   23.  Lifters O.D. .982" minimum, 1.005: maximum. 1.606" maximum overall length. Champhering at bottom of lifter bore for clearance purposes only. Max I.D. of chamber is .500. (the intent of this is not to back face lifter bore area.) Billet lifters permitted. Check to stock dimensions.

   24.  Rod bolt lock, washers and dipper are non-tech and optional. Stock rod bolts must be used. The dipper area only of the Raptor II 55207 rod is non-tech. Oil hole size Non-tech. No .020" undersize rods dimensions.

   25.  Any unmodified, series produced aluminum alloy rod that is available to the karting industry is allowed. Rods other that the Briggs factory rod may be no lighter than 135 grams with bolts and inserts, if used. Rod length, from bottom of wrist pin hole to top of crank hole must measure between 3.120" and 3.143".

   26.  Wrist pin. Maximum I.D. .290: Maximum O.D. .490" Raptor III wrist pin I.D. .281 Max., O.D. .490, Length 1.731 +/- .005.

   27.  Piston. Minimum length 1.869" Minimum top of wrist pin to top of piston. .937". IC engines may run IC or cool bore piston. Raptor III piston allowed, arrow facing coil or PTO. Piston length 1.672 + or - .005. Top of piston hole to top of piston .937 + or - .005.
    a.  Raptor III ring .090 min. width, . 058 + or - .005 thickness.
    b.  Raptor III oil ring .070 min. width, .100 + or - .005 thickness.

   28.  Stock type cool bore rings only. No IC rings allowed. Machining back side of rings allowed.
    a.  Top groove - compression ring installed. Minimum width: .095". (No chrome ring or expander under ring.) May or may mot have bevel.
    b.  Middle groove - oil scraper ring installed with outside scraper groove down. Minimum width .095". (No expander under ring.)
    c.  Bottom groove - one piece oil ring installed either way, and no three piece or four piece oil ring from chrome set allowed. Minimum width .085".

   29.  Heat treating of stock crankshafts legal. Bushing type PTO journal crankshaft may be turned down to allow the use of bearing. Cam gear must be in place on an unaltered key.)

   30.  Stock Briggs bushing #399268 or #297565 may be installed on flywheel side. Inspect block for alterations and reworking. Blocks welded for broken rods are legal if not used to disguise modifications. Minor welding to lower exhaust bolt hole is allowed for repair (weld cannot protrude into exhaust port). Reinforcement or repair of lifter boss area is allowed. Installation of bushing guide to help reinforce lifter bore area allowed. Removal of governor mandatory. PEER 6205-14 or equivalent 9 ball, steel separator, ball bearing allowed on flywheel side of ball bearing cranks. This bearing is used without sleeve. Extra .125" hole may be added on flywheel side of block for better bearing lubrication. After-market PTO bearing of non self-aligning type, with or without shields, is permitted. No ceramic bearings allowed.

   31.  Check valve seat heights 5.485: minimum/ 5.520" maximum. Install a .500: rod in place of cam and replace side cover. Measure though the valve guide from top edge intake or exhaust valve seat. Lifter bore and valve guide bore must accept seat height gauge rod.

Header or Muffler

  1.  Header or muffler must extend beyond fuel tank, but not to extend past rear bumber. Minimum 1.990" washer or flange mandatory on pipe end. No sharp edges. Washer thickness. 075" minimum.
  2.  Exhaust header end or muffler may not protrude inside of port.
  3.  Header support allowed. Bracket to support header or muffler allowed. Bracket may not be secured under more that 4 head bolts.
  4.  Must be fixed position pipe. No "slippy" pipe.
  5.  No extra tubes to, in or through header allowed.
  6.  Hole for exhaust thermocouple allowed. Thermocouple must be in place.
  7.  Loop pipe must be heat wrapped for safety.
  8.  Header and Mufflers will be required on all 4-cycle engines. RLV B-91 on all stock motors.
  9.  Block savers/ exhaust rotator allowed.
  10.  Bolt or studs securing header must be safety wired. Muffler must be safety wired through a hole in the header brace and perforations on end of the muffler. Do not weld on or drill holes in the muffler.

Fuel and OIL

  1.  Any competitor spilling oil or fuel on the track will be subject to suspension. Methanol in all classes. NO ADDITIVES
  2.  Fuel may be pumped around or tested by any means available to KART officials. Violators may be suspended.
  3.  Crankcase content are subject to test, at any time, for dangerous, oxygen bearing or flammable vapor producing substances, which are prohibited.
  4.  Flame test procedure is as follows:
  5.  Drain about 1 fl. Oz. of crankcase oil into a large steel spoon or ladle
  6.  Apply heat to the bottom of spoon with propane torch while checking the surface temperature of the oil with an infrared temperature gun.
  7.  When the oil temperature is between 250 and 300 degrees maximum, pass the flame 3 times over the oil apporximately 1-inch above the surface. Do not touch the flame to the surface of the oil.
  8.  If the oil ignites and continues to burn when the flame is removed, it is illegal. If the oil flashes and the flame goes out immediately when the torch is removed, the oil is legal. Modifications of the method are acceptable if the following points are observed: Oil temp never exceeds 300 F. The flame source does not torch the surface of the oil. Continued burning of the oil is necessary for illegality.

SPECIAL RULES

  1.  No pressure tank in any classes.
  2.  Oil catch container overflows are mandatory in all 4-cycle classes. Overflow system subject to tech.
  3.  Tach and temp gauges are subject to tech inspection and are legal in all classes No sealer or paint may be used on any gasket or sealing service. Sealer may be used as an exhaust gasket in all classes.
  4.  Engine will be teched the day it is raced. Engine can be held up to 72 hrs. Carb saver brackets allowed. If head to carb type is used, the bracket and/or filter adapter must remain lower than the top edge of the carb inlet (type A adapter). Bracket may not alter tech dimensions (type B adapter).
  5.  Engines may be checked for air leaks.
  6.  There is no tech on the quantity of holes in the flywheel screen but if there are holes they cannot be uncovered at any time during the race.

Fuel Tech

There are two field tests for checking methanol. Any other approved test means available may be used. Either or all tests may be used.
    1. In a clean bottle add ½ fuel and ½ distilled water. Mix and let set. A legal sample will mix and become clear almost immediately. If the sample turns milky or is contaminated by foreign material it is considered illegal.
    2.  Specific gravity. Check the specific gravity of the methanol using the following chart + or - .003 specific gravity variation.

Fuel Temp	Specific Gravity	Fuel Temp	Specific Gravity	Fuel Temp	Specific Gravity
35	809	58	797	80	785
38	807	60	796	83	783
40	806	63	795	85	782
43	804	65	794	88	779
45	803	68	793	90	778
48	802	70	792	93	776
50	801	73	789	95	775
53	799	75	788	98	773
55	798	78	786	100	772