American Roadracing 450cc Dirtbikes | Super Singles!

The Father of Supermoto seeks to revolutionize American Roadracing with a spec series based on 450cc dirtbikes

One of our features this month is about the nascent Moto-ST endurance racing series, and that organization's attempts to produce a product that is more competitive and compelling for American racing enthusiasts than the current offerings from the AMA (see page 92). It turns out that NASCAR-backed Moto-ST is not the only party interested in reinventing motorcycle roadracing in America. Gavin Trippe-the mind behind the original ABC-TV Superbikers racing series that ran from 1979 to '85-is also working on a new roadracing series utilizing inexpensive, specially constructed racebikes built from 450cc motocross machines. With help from industry power brokers Troy Lee and Roland Sands, enthusiastic support from the Japanese Big Four and the attention of AMA and WERA, it looks like Trippe is headed in the right direction.

Trippe got the idea to roadrace dirtbikes after watching 450cc supermoto machines dominate the AHRMA Sound of Singles class at Mid-Ohio's Vintage Motorcycle Days last year. Trippe eventually acquired a Honda CRF450X and delivered it to former AMA 250cc Grand Prix Champion and accomplished custom bike builder Roland Sands, commissioning a full-on roadracing conversion. Sands was skeptical, but once he tilted the chassis forward and grafted on a set of CBR forks, resulting in a geometry very similar to the Yamaha TZ250 he used to race, he came around. A few weeks later Sands was circulating Willow Springs on a prototype.

Trippe instructed Sands to minimize the necessary modifications (i.e., no cutting, welding or moving the engine), to keep the so-called 450Moto bikes ( inexpensive and accessible to anyone with a desire to race. "I didn't want this to be like AMA flat-track, where you need a $12,000 frame for your 450 racer to be competitive," Trippe says. The 450Moto bikes use the factory frame, subframe, swingarm and fuel tank. Sands is presently developing a conversion kit, including bodywork and brackets, so interested parties can roll their own 450Moto racers.

If you use top-of-the-line parts such as the custom hlins fork and shock on the prototypes, Trippe estimates the 450Moto conversion would cost $7000-$8000. Repurposing the stock fork (using parts currently under development by Race Tech) and utilizing other MX bits would substantially reduce that figure. Considering that Japanese manufacturers sold nearly 100,000 450cc off-roaders in America over the last four years, donor bikes are readily available for well under $5000, which should make it easy for anyone to build a competitive Moto450 racer for significantly less than a 600cc Supersport, for example. Capable of producing 60-65 bhp in a reasonably reliable state of tune, with a race weight of around 240 pounds, the 450Motos should be quite entertaining on the track.

Trippe is envisioning a rules-limited "spec" series that is carefully regulated to ensure close, competitive, multi-brand racing. "I don't want it to be about who can build the fastest bike," he says. "It will be a great, competitive series for privateers, an excellent opportunity for dealers to get involved in racing cheaply, and a great tool for younger riders to learn about braking and cornering before moving on to bigger, faster machines."

Trippe's concept has captured a lot of attention in a short time. After Sands' initial Honda prototype broke cover early this summer, Yamaha and Kawasaki provided bikes to Sands to undergo 450Moto conversions. Yamaha even displayed the WR450-based prototype at its national dealers' meeting to gauge interest. Trippe also presented the concept to the AMA as a potential support class, and says the sanctioning body is interested as well. If all goes according to plan, Trippe hopes to introduce a 10-race 450Moto exhibition series run in conjunction with WERA-sanctioned club races in '08, followed by a slot in the AMA national program in '09. With the AMA restructuring its racing classes right now in an effort to eliminate redundancies, the timing couldn't be better to present a competitive, contingency-driven, privateer-friendly, single-cylinder racing option.

Trippe insists the time is right. "There's so much manufacturer attention on the 450cc category," he says. "All the manufacturers make them, and not too far down the road there are going to be all sorts of 450cc streetbikes as the youth market and insurance costs become bigger issues. There's so much interest here, on so many levels-it will definitely go somewhere if we put together the right package."