Ultima: Classes, Eligibility

12.2.4 GRAND PRIX 500: Certain post-1977 motorcycles, 325-500cc two-stroke and 580cc four-strokes. The year of manufacture is not important, as long as the motorcycle meets the class formula, with a few exceptions (see below). • 1978-’81 Can-Am Qualifier and MX 370/400 up to MX6 are allowed. • 1987-’92 CZ 400 is allowed. • 1978-’84 Husqvarna CR, XC, OR, WR 390-500 two-strokes are allowed. • 1978-’84 Husqvarna 390, 420 and 500 Automatics are allowed. • 1978-’81 Maico 400-440-490 are allowed. • 1978-’80 Mugen 360-kitted Honda CR250 is allowed. • 1982 Suzuki DR500Z is allowed. • 1982 and later Can-Am Sonic with Rotax engines are prohibited. See Ultima class. • 1981-model Honda and Suzuki are prohibited. See Ultima class. • 1983-’84 Husqvarna TE, TC, TX four-Stroke 510s are prohibited. See Ultima class. • 1980 and later Kawasakis are prohibited. See Ultima class. 12.2.5 GRAND PRIX FOUR-STROKE: Certain 185-580cc four-stroke-powered motorcycles that came just after the Historic Four-stroke class period. Eligible motorcycles and modifications include: • All Honda XR185, 200, 250 and 500 models produced with dual-shock rear suspension • Four-valve CCMs • Yamaha TT250 and 500 with more than 9” of suspension travel, front and rear • Suzuki DR models to include the 1982 DR500Z • Kawasaki KLX models • Period specials that meet the class requirements • Can-Am Sonic and Husqvarna 510TE, TC and TX models are prohibited (See Ultima Four-stroke class.)

12.3 ULTIMA - CLASSES AND ELIGIBILITY

The Ultima classes are for machines that bring us to the brink of the modern motocross motorcycle. Generally, the distinguishing formula for the Ultima classes is as follows: Motorcycles produced with liquid-cooling and linkage-type rear suspension are acceptable, but those produced with disc brakes or any type of power-valve mechanism built directly into the engine are not. 12.3.1 TECHNICAL SPECIFICATIONS: Upside-down forks, such as Simons and early White Power, are allowed only on Ultima-class motorcycles, as are aftermarket single-shock frames (such as C&J). 12.3.2 ULTIMA 125: Certain motorcycles 88-125cc that were produced within the guidelines of the Ultima-class specifications. Eligible machines, and exceptions, include but are not limited to: • Honda CR125 up to 1983 is allowed. • Suzuki RM125 up to 1984 is allowed. • Yamaha YZ125s, up to 1982-’84 with YPVS system, are allowed. (Note: These are the only eligible motorcycles allowed to use a power-valve mechanism.) • 1982 and later Kawasaki 125s are prohibited. • 1985-model Husqvarna 125 is prohibited.