WKA America Grand Nationals

Overview

Class Structure

  • Age: 5-7 (attained)
  • Numbers: 00-99
  • Engine: Comer C51 only
  • Fuel: Spec – 87 Octane
  • Weight: 150 lbs.
  • Tires: Bridgestone YLC – 10×4.50 (33 1/4 max circumference)
  • Gear Ratio: 10/89
  • Notes: See Section 900 for chassis and bodywork specifications
  • Age: 7-10
  • Numbers: 00-99
  • Engine: Vortex Micro ROK with manufacturer-supplied restricted exhaust header
  • Carburetor: Dellorto
  • Weight: 230 lbs.
  • Tires: Bridgestone YLC – 10×4.50–5
  • Gear Selection: 11/82 – 10/79
  • Notes: (1) Must run same tires for entire event. (2) Tires must be new to start each event. (3) Cadet or standard size chassis permitted.
  • Age: 8-12
  • Numbers: 100-199
  • Engine: Vortex Mini ROK with manufacturer-supplied exhaust
  • Carburetor: Dellorto
  • Weight: 245 lbs.
  • Tires: Bridgestone YLC – 10×4.50–5
  • Gear Selection: 11/82 – 10/79
  • Notes: (1) Must run same tires for entire event. (2) Tires must be new to start each event. (3) Cadet or standard size chassis permitted.
  • Age: 8-12
  • Numbers: 100-199
  • Engine: IAME Mini Swift engine with manufacturer-supplied exhaust
  • Carburetor: Tillotson HW-31A
  • Weight: 245 lbs.
  • Tires: Bridgestone YLC – 10×4.50–5
  • Gear Selection: 11/82 – 10/79
  • Notes: (1) Must run same tires for entire event. (2) Tires must be new to start each event. (3) Cadet or standard size chassis permitted.
  • Age: 11-15 (attained)
  • Numbers: 800-899
  • Engine: IAME KA100 / Vortex ROK VLR
  • Carburetor: As supplied by the manufacturer
  • Weight: 320 lbs.
  • Tires: Bridgestone YLC – 10×4.50-5 / 11×7.10-5
  • Timing: VLR .106″ MAX / KA100 .106″
  • Notes: (1) Must run same tires for entire event. (2) Tires must be new to start each event.
  • Age: 12-15
  • Numbers: 700-799
  • Engine: IAME X30 with 26mm exhaust header
  • Carburetor: As supplied by the manufacturer
  • Weight: 330 lbs.
  • Tires: Bridgestone YNB – 10×4.50-5 / 11×7.10-5
  • Notes: (1) Airbox required. (2) Max exhaust length (as raced) is 16 3⁄4” as measured from the back side of the header flange, around the right side of the header, connector and pipe to the first weld at the end of the divergent cone.
  • Age: 12-15
  • Numbers: 200-299
  • Engine: Vortex ROK GP with manufacturer-supplied exhaust restrictor
  • Carburetor: As supplied by the manufacturer
  • Weight: 320 lbs.
  • Tires: Bridgestone YNB – 10×4.50-5 / 11×7.10-5
  • Notes: Airbox required.
  • Age: 7-12
  • Numbers: 400-499
  • Engine: Briggs LO206 Sealed Engine
  • Exhaust: RLV #5506 or #5507
  • Carburetor: As supplied by the manufacturer with Locking Cap #555726
  • Slide: Briggs Green .490 Part Number #555740
  • Fuel: Spec – 87 Octane
  • Weight: 265lbs.
  • Tires: Bridgestone YLC – 10×4.50–5
  • Notes: (1) Must run same tires for entire event. (2) Tires must be new to start each event. (3) Cadet or standard size chassis permitted.
  • Age: 15+
  • Numbers: 900-999
  • Engine: IAME KA100 / Vortex ROK VLR
  • Carburetor: As supplied by the manufacturer
  • Weight: 360 lbs.
  • Tires: Bridgestone YLC – 10×4.50-5 / 11×7.10-5
  • Timing: VLR .120″ MAX / KA100 .106″
  • Notes: (1) Must run same tires for entire event. (2) Tires must be new to start each event.
  • Age: 15+
  • Numbers: 300-399
  • Engine: Vortex ROK GP with manufacturer-supplied exhaust
  • Carburetor: Dellorto
  • Weight: 355 lbs.
  • Tires: Bridgestone YNB – 10×4.50-5 / 11×7.10-5
  • Notes: Airbox required.
  • Age: 32+ or 190 lbs+ body weight
  • Numbers: 600-699
  • Engine: Vortex ROK GP with manufacturer-supplied exhaust
  • Carburetor: Dellorto
  • Weight: 390 lbs.
  • Tires: Bridgestone YNB – 10×4.50-5 / 11×7.10-5
  • Notes: Airbox required.
  • Age: 15+
  • Numbers: 400-499
  • Engine: Vortex ROK Shifter with manufacturer-supplied exhaust
  • Carburetor: Dellorto
  • Weight: 395 lbs.
  • Tires: Bridgestone YNB – 10×4.50-5 / 11×7.10-5
  • Notes: Airbox required.
  • Age: 32+ or 190+ bodyweight
  • Numbers: 500-599
  • Engine: Vortex ROK Shifter with manufacturer-supplied exhaust
  • Carburetor: Dellorto
  • Weight: 410 lbs.
  • Tires: Bridgestone YNB – 10×4.50-5 / 11×7.10-5
  • Notes: Airbox required.