Backtrack: A replica XR750 tracker from Gasoline
There are a handful of classics out there that look amazingly ‘right.’ In that category, we’d put machines like the Norton Manx, the Moto Guzzi Le Mans, and the early Honda CB750s and Kawasaki Zeds.
In the V-twin world the Harley-Davidson XR750 fits into that category. But it didn’t just look good: it was also one of the most successful race bikes of all time. The XR750 won an incredible 29 AMA Grand National Championships, and garnered even more fame as the weapon of choice for Evel Knievel.
It would be borderline criminal to hack up an original XR750, but in Australia there’s a guy who can channel the riotous world of 1970s flat track on the street. He’s the lucky owner of this custom Sportster called ‘GAS XR’—a clever XR750 replica from Australia’s Gasoline Motor Co.
What appears to be a mint-condition historic machine is actually the past reimagined with technical precision. “This was built for a customer who wanted to honor the XR750’s glorious history, but make it beyond functional for road use,” says Gasoline’s Jason Leppa.
The Gasoline team, with Sean Taylor helping Jason, have used the engine and half a chassis from a modern 883 Sportster. And despite the retro racer looks of this Harley, it’s road legal—with additions like LED headlights, mini indicators, a custom EFI system package, plus the stock niceties such as ABS brakes.
The front is sporting Ceriani-style triple trees and forks, overhauled with a Monotube cartridge kit, and a matching riser clamp housing a compact Motogadget speedo.
The wide stainless steel handlebars were shaped and polished by metal specialist Kansai Giant, who played a big part in the fabrication of this machine.
Squeezed onto the minimal handlebar setup is a Prism Supply Co. single cable throttle, plus a front brake reservoir and polished aluminum hand controls from Kustom Tech. As well as the speedo, Motogadget supplied the warning lights, grips and push-button switches—which were stripped and polished to match the chrome.
The 883 engine thankfully received a little attention too. A Vance & Hines Fuelpak optimizes the fueling, with increased airflow from an S&S filter and a set of custom bent slash cut pipes, a replica shape from the 1970s.
And since trackers don’t have belt drives, power now hits the back wheel via a chain conversion kit secured with an HHB sprocket locker.
The little fuel tank was made by Phil Little, a Minnesota-based fiberglass specialist with a big reputation in the industry. “The tank is so little, an external fuel pump needed to be custom-mounted, along with a fuel pressure regulator and Proflow fittings,” says Jason.
“But the most challenging components of the build were the subframe and rear shocks,” he adds. “The original subframe was modified to work with the new tail piece, and a set of 15” YSS shocks.”
A fresh coat of powder coat hides evidence of the mod. But Jason’s favorite feature is the intricately handmade oil tank—an exact replica of the 70s original.
The AMA’s flat tracker standards call for a set of 19-inch wheels, so Gasoline have laced up a set of 4-inch wide custom aluminum rims using stainless spokes and nipples—with the original ABS bearing custom fitted. To maintain the vintage appeal, they’ve opted for Firestone rubber.
The new electrics called for some hidden tech, though. “We created a front-to-back wiring harness with a push button control module, utilizing the OEM body control module and ECU,” says Jason. “The ABS, keyless and immobilizer systems were kept in place.”
The control module is also connected to dual-function rear blinkers and ‘Atto Dark’ front blinkers from Kellermann, and a LED light bar under the race plate. The traditional front plate als hides vital electrical components, in a 3D-printed housing box.
Converting a 50-year-old XR750 for street use can be done, but it would test the patience of even the most accomplished builder. And probably incur the wrath of a bank manager too. So Gasoline’s approach is an intriguing halfway house, marrying the style and stance of the original with modern usability. “The premium components make it a joy to ride,” says Jason. “It feels completely modern, with impeccable fine detailing.”
Well, he would say that, wouldn’t he? But we believe him, and would love one of these in the garage.