1974 Harley-Davidson XR750 Dirt-Tracker

One bike, two champions

1974 Harley-Davidson XR750 Dirt-Tracker

Any bike that carries a rider to an AMA Grand National Championship is special. But this 1974 Harley-Davidson XR750 holds an interesting distinction. It was ridden by one national champion, and then tuned by him to help carry another champion to the title.

Now owned by Carl Fronk of Langhorne, Pennsylvania, this XR750 was originally ridden by Mert Lawwill, who had won the AMA’s premier Grand National Championship, combining dirt-track and road-racing events, in 1969.

Although the XR was a new bike, developed by Harley for the 1972 season, Lawwill was never one to leave a stock machine alone. So his XR750 featured Axtell heads, along with Lawwill’s own special-grind cams, plus a Lawwill chassis and magnesium cam cover, all of which added to the attraction when Fronk got a chance to buy the bike.

“I knew that it was one of the last bikes that Mert had ridden, and that he massaged his bikes personally,” Fronk says. “And I thought it would be neat to have a bike that Mert built.”

But that’s just half the bike’s heritage. In 1981, after his retirement as a racer, Lawwill joined forces with Kenny Roberts in a team that was designed to develop a new Yamaha V-twin dirt-tracker.

With Mike Kidd and Jim Filice as the riders, the Roberts/Lawwill team set out to make the Yamaha competitive. But the team truck always carried Lawwill’s old XR, just in case.

Early in the season, Kidd won the Ascot TT, and suddenly, he was in the midst of the series points battle. So when the Yamaha was slow to develop, the team decided to keep him up to speed by using the Harley.

Over the course of the season, Kidd edged out Gary Scott by just 5 points—200 to 195—to take the Grand National Championship. And many of those points were earned on this machine.

Lawwill and Kidd have been inducted into the Motorcycle Hall of Fame, and the motorcycle they both rode was previously on display in the Motorcycle Hall of Fame Museum at AMA headquarters in Pickerington, Ohio.

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Air-cooled 4-stroke V-twin


Kosman magnesium rear caliper


Lawwill chassis with round swingarm

Carl Fronk

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