New Dirt-Track Class?
NEW DIRT-TRACK CLASS?
IS THE MOTORCYCLE PICtured here the prototype for a future, productionbased dirt-track racing class? Could be, if the results of a recent track test session are any indication.
Pro racers Chris Carr and Mike Hale were invited by the AMA last April to help evaluate the performance of a pair of Harley-Davidson Sportster-based dirt-trackers. The bikes, built by Jim Kelly of Bartels’ Performance Products, are very similar in tune to the Sportsters that compete in the AMA’s Twin Sports roadracing class. Engine internals are stock, and the only external changes are the fitment of dirttrack-style high-pipes and the elimination of the bikes’ starter motors.
The bikes’ chassis are similarly production-based. Besides stripping all street equipment, each of the bikes’ front-brake systems was removed, and rear shocks were replaced with 2-inch-longer units to quicken steering. The stock seat is replaced with one from an XR750 racebike, the handlebar changed, and the left-side footpeg and gear-shift lever altered for additional cornering clearance.
The bike shown here wears 19-inch front and rear wheels, and Goodyear tires, but the stock cast wheels and 18-inch spoked wheels were also tried, shod with hand-cut, DOT-approved street tires.
The results were promising.
“I was very surprised at how well they worked,” said Hale. Carr thought the bikes felt very similar to proper dirttrack racers. “The biggest difference is things happen slower,” he said.
What’s all this mean? “Right now, probably for the first time, there is long-range planning going on for dirt-track racing,” explained Merrill Vanderslice, national technical manager of the AMA. “It’s already a good show, but it has the possibility of dying from the bottom up due to lack of participation.”
Still, the AMA does not view a Sportster class as a replacement for its ailing amateur DTX program, which utilizes modified motocrossers.
“We see this as an option for Pro dirt-track racing, probably as a support class,” Vanderslice continued. “Something will definitely come out of it, but it’s too early to tell.”
Brian Catterson
