RULE CHANGES FOR 2011 AT THUNDER HILL SPEEDWAY-
NEW CLASS FOR 2011 AT THUNDER HILL SPEEDWAY! - SPORTSMAN CLASS (flat karts)
The intent of the sportsman class is to be fun and affordable for the seasoned veteran or as a good place for new racers to start at Thunder Hill Speedway!
Sportsman class rules 2011:
All Body and Chassis rules are the same as all other THS flat kart speedway chassis rules (IKF Body rules)
*14 years old and up
* 370 lb minimum kart and driver
* Briggs Animal LO206 sealed gasoline engine with rev limiter (6100 rpm max) as supplied from Briggs and Stratton ( 2011 IKF rules apply sec 721)
* Engine must be ran as supplied by Briggs and Stratton, including recoil starter
* Spec header (RLV 5506) and muffler required for this class, NO other header will be allowed to compete
* Gasoline only, no additives, no ethanol blended fuel 89-92 octane only
* Any centrifugal clutch with a maximum of 3 springs and 3 shoes is allowed. No alterations to clutch is allowed, except springs, clutch coolers not allowed * NO single or multi disc clutches allowed
* #35 chain only! No 219 chain allowed
* Steel axle only
* Sportsman Spec tire rule: Must have Burris SS-33A series tires on all 4 corners only! We will durometer tires!
* No prepping of tires, maybe washed with drinkable water only! If you are caught prepping tires you will not be allowed to race. We will durometer tires!
Rule 721.26- HAVE FUN!
Novice class 2011-
Any color clone 6.5HP / 196CC engine (governor and governor linkage may be removed!)
** Engine internals must be stock and must meet 2011 IKF tech rules section .722
** .375 ARC Red Plate new for 2011
** Stock muffler or AM(After Market) header ok, AM header .675 ID / .750OD, max length 15”, min length 10”, MUST have flare or flat washer welded to the end of the pipe, if using muffler on AM header it MUST be the RLV B-91 Mini muffler or the BS CM-2 AKRA muffler ONLY, muffler may not be modified in any way and must meet IKF / AKRA spec.
** All AM headers must be wrapped from 1” above mounting flange to within 1” of end of pipe or 1” from muffler mount
** AM mufflers must be secured to header with a strap and clamps or wired from end of muffler to engine
** Removal of oil sensor is allowed
** AM air filter and adapter allowed, must meet 2011 IKF spec
** Removal of top mounted fuel tank is allowed for safety, AM single stage fuel pump allowed, must be pulsed from rocker cover only
** Gasoline only 86-93 octane only, NO additives allowed** No ethanol fuel allowed
** 13Tooth 35 pitch clutch only, must be stamped steel drum without a removable gear. Two shoe type only
** 62Tooth rear sprocket only
** 35” maximum tire circumference on right rear
** Kart weight 235 Minimum
** No drivers fairings allowed
** No tachometers allowed
** All karts must comply with 2011 IKF - BODY and chassis rules
** All novice karts must have full width rear bumper ( center of LR tire to center of RR tire, MINIMUM)
** Engine claim $200, claim does not include header, air filter, filter adapter, clutch, chain guard, throttle linkage, engine top plate if used, clutch or engine mount
Jr 1 2011-
IKF Body rules and
6.5HP clone, any color 196CC only
Engine must meet sec 722 IKF / AKRA 2011 rules, this is NOT at Builders Prepared engine! But does have complete rules for the engine
** Gasoline only, 86-93 octane only, no additives / no ethanol fuel
** ARC .425 Silver restrictor plate only
** Optional** stock flywheel or ARC 6619 billet flywheel allowed
** Any dry clutch allowed, drum or disc, must be dry clutch, no wet clutches or jack shafts allowed, any gear size
**Header: Any header ,maybe used, with or without muffler, NO LOOP pipes, if using a muffler it must meet 2011 IKF / THS rules
** All headers must be wrapped from 1” above mounting flange to 1” from muffler mount or if no muffler wrap must come to within 3” from flare or washer
** Engine timing, Not a tech item for 2011 at THS
** ALL other engine rules must meet sec 722 IKF rules for 2011
** Minimum weight 250 lbs
** No drivers fairing allowed in this class ( IKF rule for many years)
Jr 2, 2011-
IKF Body rules , Flathead only
IKF .500 red plate
***MAY BE LAST YEAR for Flathead in this class! 2012 may be clone or LO206 Animal! Keep this in mind over the summer months!
St Med 2011-
IKF Body rules, header must be wrapped
Adult Animal Hvy 2011-
IKF Body rules, header must be wrapped
ALL headers must be wrapped per IKF rules ( safety issue)
All Flat kart classes:
This is the 2011 IKF rule and rule number;
Must meet IKF specifications for the given class. Must present no hazard to competitors
Speedway body work / Aerodynamic Regulations
The intent of the following regulations is to limit aerodynamic devises used on all types of speedway racing
Usage: Nose is required on all 4cycle Speedway racing karts and is optional on 2cycle karts.
Nose cone must be a minimum of 8” high and a maximum of 18” high. Nose piece shall not be inclined more than 1-14” from vertical at a height of 6” from the ground. Nose piece shall not be wider than 3” per side than the tires / wheels measured at the centerline of the frt axle with the wheels straight ahead. Outside of front tires cannot / shall not be covered, must be exposed. Nose shall not cover drivers feet, i.e. feet and controls must be visible.
Materials and mounting
Nose must be constructed of high strength plastic of fiberglass and must be securely mounted to kart. Bottom of nose piece may be mounted flush to bottom side of frame extending back no future than the centerline of the front axle. Top surface of nose piece may not extend rearward of centerline of front axle unless attached to side pods or panels of full body.
No additional protection devices such as rub strips, braces, etc are allowed internally or externally on the nose piece. Foaming of the nose piece on the inside is allowed. Patching the nose piece is allowed but is subject to tech. Taping is acceptable repair.
Side panels or pods of flat or 90 degree style or CKI style pods maybe used. Must be securely mounted. Side panels and pods must be void of sharp edges. No metal panels or pods allowed.
Maximum height will be 14” from the ground measured from a point 12” rearward of the front axle centerline.
Ground clearance: Minimum height of side panels / pods is ¾” from ground
90 degree panels maynot cover any part of the drivers body. Distance from the seat to panel 1” minimum, all areas. Minimum opening area forward of seat back to rearward area of front tire is 22” minimum measured with tires straight ahead. Panels maybe connected to nose piece. Panels or pods maybe a maximum of 4” per side wider than the rear tires.
If side panel extends rearward of the rear tires it must not extend past the rear bumper
*Maybe used on side panels or pods, may not be metallic, must be of flexible plastic material
* May not be thicker than ½”, ends of strip must be beveled or rounded toward flat of side panel
* Must be attached with button type head screws, max of ¼” diameter, and flat washers or pop rivets
Maybe installed more than 26” to protect driver, Fairing or steering wheel cannot be installed in such a way that it obstructs driver vision. Fairing shall be no higher than the drivers eye level when sitting in kart in normal manner
Width: Maximum width allowed is 14” using a cord / string
Clearance: Must have a minimum clearance of 1” between front of faring and nose piece or side panels, fairing shall not connect to nose piece
** Class restrictions:
Steering column fairing or windshields are not allowed in any Junior 1 or rookie / kid kart classes.
The are the general body rules and cover pretty much everything you asked for I hope. If not let me know and I’ll send more info.
You also may want to put on your web site the information on the chest protectors required for J1 and Novice.
All drivers in novice and Junior1 are required to have a chest protector “must have SFI certification 20.1”
Jr Wing 2011 -
Same as last year with the following changes:
**300 lb. weight rule (was 275 lb)
**Animal header: 24 ” max length from header flange ( mount) to end of muffler or flare. Headers MUST be wrapped from 1” above flange to muffler or flare. ( safety issue)
** Header must be “J” style pipe only and MUST stay within the frame rails, muffler if used must be secured per IKF engine rules, header that exit outside the frame rails will not be allowed to compete. Header / muffler may not extend behind the rear bumper
** Gasoline only, 86-93 octane, no ethanol fuel or fuel additives allowed
** Clone engine allowed in Jr.Wing class:
** Engine per section 722 with the same THS changes as the JR1 class structure. No restrictor plate required
** MUST use billet ARC 6619 flywheel
** Header must stay within frame rails ( same as Animal engine) and must be wrapped
** Any clutch maybe used ( drum or disc, must be dry type only)
125cc Wing Kart rules for 2011-
This is a stepping stone class for kids that we want to keep affordable and enjoyable-
-Single cylinder, 2-stroke, Honda, Yamaha, Kawasaki or Suzuki, dirt bike engine (same as 2010)
-No big bore kits (135cc maximum cylinder displacement) (same as 2010)
-No lightweight cranks or stroker kits (same as 2010)
-Must have factory stock stroke and rod length as per manufacturer engine specifications for the year and model of your engine (same as 2010)
-Must have complete working clutch, no slipper clutches (same as 2010)
-After market pipes OK (same as 2010)
-After market reeds OK (same as 2010)
-Pump gas only (No Methanol) (same as 2010)
-No Nitrous Oxide (same as 2010)
-Must have factory, stock ignition for your engine (no after market or adjustable ignitions) (new for 2011)
-Must have factory, stock rubber intake for your engine (new for 2011)
-Single fuel pump or safely mounted gravity fuel tank (new for 2011)
-Single carburetor only, No Fuel injection or pump around system of any kind (new for 2011)
-No Rotary engines (new for 2011)
-Weight 350# (new for 2011)
2011 Quads- Will be a trophy class with a lower entry fee (same as karts)
2011 Wingless Warriors- Can run your choice of wing kart hood and tail, but no extra spoilers
2011 - 250 and 500 Winged Outlaw rules the same as 2010