Dirt-Track Is Dead, Long Live Dirt-Track
Dirt-track is dead, long live dirt-track
Is dirt-track a dying sport? It’s been declared dead or dying for what seems like decades now. Well, if the packed stands and overflowing parking lot at the 2001 Daytona Short Track are any indication, dirt-track is alive and well.
Still, the two major sanctioning bodies—AMA and Formula USA (nee SFX, formerly PACE)—are trying to give the sport more real-world relevance than its predominantly Harley-Davidson XR-750-based fields currently provide.
When the Formula USA series was established last year, rules were structured so that through the use of restrictors, smaller-displacing Singles could be raced competitively with the popular 600cc Rotaxes in its Pro Singles class.
The latest development in the AMA series was the establishment of a Pro Sport class with a displacement limit of 505cc. Such a bike can legally be run with the 600cc Rotaxes that currently dominate the short-track and TTs, but the Pro Sport class was established to give teams an opportunity to develop a bike in a less intense setting than the Grand Nationals. The plan is that next year GNC Singles will be limited to 505cc, hopefully broadening the spectrum of brands that will participate in the races.
Who will be there? Suzuki, for one. A DR-Z400E-based dirt-tracker made its debut at Volusia Speedway Park at the beginning of Daytona Bike Week. The machine was assembled in a last-minute effort inside the Team Powell truck at Volusia with the help of Suzuki's Craig Williams, a longtime dirt-track fan and former racer who's worked at American Suzuki for 25 years. He's long been a proponent of Suzuki becoming more in volved in dirt-track racing. In fact, he participated in the initial, TL 1000-based SuperTrackers effort, not to mention the limited campaign of a DR500 Single ridden by Ronnie Jones in the 1980s.
It was no small feat to get the DRZ400 engine up to the displacement limit. Using a readily available JE piston, they increased the bore 4mm to 94mm, then “backed into” the displacement limit on the stroke side with an increase of 9.5mm over the stock 62.6mm stroke. The engine now measures 503cc, up from 398cc.
The connecting rod is one manufactured for NHRA drag racing for use in the old Suzuki GS1150 engine. Williams’ plan, however, is to manufacture something shorter that requires fewer spacers under the cylinder, which is currently raised more than 14mm. He added, “The starter’s gone, the counterbalancer’s gone and Falicon rebalanced the crankshaft so it doesn’t vibrate, but we may try it with the couterbalancer again, to see what it does to power delivery.”
Additionally, a readily available Yoshimura kit for the DR-Z, including cams, valve-spring pieces and a black box that allows overrev was used. How’d it run? Pretty good for a first go, actually. “We ran it in the (AMA amateur) Hot Shoe races at the Volusia HalfMile with Noot Irvin, an old expert who retired and has come back. He got third in his heat and fourth in the main,” Williams said.
Team Powell’s GNC and SuperTracker rider J.R. Schnabel also rode the bike at the Hot Shoe event, but failed to qualify due to a crash. Still, he was impressed. “It was really close to what a 600 Rotax is,” said Schnabel. “It’s really surprising that it’s so comparable, but it’s good because that’s what we need: a bike that can run with the Rotaxes. It does, at least off corners.”
The latter point highlights the engine’s main weakness at this stage: lack of top-end oomph. Both Schnabel and Williams said they need to tune the engine to rev longer so it keeps pulling at the end of the straights.
Development will continue, and Williams hopes that either full kits can be made readily available or aftermarket companies will manufacture the necessary items so that those who want to build a dirt-tracker can do so easily and affordably. Also, Suzuki has more than doubled its contingency support for the AMA and Formula USA series over last year, now offering more than $300,000.
Williams is also involved in projects that include a 750cc Twin based on the SV650, and a TL1000 with reduced displacement that could run with XR750s. “I have asked the AMA to let me de-bore some 1000s to 750cc and they said, ‘Fine, bring ’em on,’ ” Williams said. “I’ve gotten good cooperation from the AMA to meet their program. We want to support this."
Mark Hoyer
