1984 Harley-Davidson XR-1000 Sportster
With an experienced team and a lot of data.
The Harley-Davidson XR-1000 was developed in 60 days to enable the company to enter the 1983 Battle of the Twins series. Homologation required that 200 such bikes be built, but the best story surrounds the first. “Lucifer’s Hammer”, as it became known, had been Mark Brelsford’s factory ride at the start of the 1973 season. At Daytona, he collided with Larry Darr, and his 750 TT burst into flames. The blaze was snapped by a photographer and the shot was widely circulated.
The burned bike sat at the factory for 10 years until the Battle of the Twins (BOTT) became the newly formed fourth class to run at 1982’s Daytona Bike Week. Harley-Davidson racing boss Dick O’Brien rebuilt Brelsford’s old bike as a 1,000 cc racer and Jay Springsteen rode it to victory at the 1983 Daytona BOTT race, beating the Ducatis.
Gene Church had been very successful riding a Don Tilley Harley in the AMA 750 cc class, and when Springsteen went back to Grand National racing, O’Brien offered Lucifer’s Hammer to Tilley for Church to ride. Church won the BOTT championship in 1984, ’85 and ‘86. After Ducati rider Marco Lucchinelli congratulated him for a 156 mph lap in 1985, Church adjusted the carbs and did 170 mph.
The initial development program was no cakewalk, as O’Brien battled to combine 750 TT and XLX Sportster parts. A stock Sportster bottom end was used, with special heads, and the engine was fitted into an XLX chassis with Showa front forks. New iron cylinders were made, new aluminum pistons and and new rods. Bigger fins were accompanied by an oil cooler. New alloy heads were cast, with larger valves and gas-flowed intakes. Twin 36 mm Dell’Orto carburetors hung on the right side of the engine, while the exhaust exited on the left.
With 10.5:1 compression, O’Brien’s racer cranked out over 100 bhp at 7,000 rpm - with a lot of vibration. The bike had a four-speed gearbox, and was stopped by 11.5-inch triple disc brakes. It rode on nine-spoke cast wheels and Dunlop Sport Elite tires. After Springsteen’s 1983 victory, O’Brien was flooded with orders, and set out to deliver.
The XR-1000 engine produced 70 bhp at 5,600 rpm (against 56 on a stock XL motor) but buyers could order a race kit to add another 20 bhp. The XR-1000 weighed under 500 lbs and the Dell’Ortos fired immediately with an electric start. The XR-1000 could do the quarter mile in 12 seconds at 100 mph, but the 2.2 gallon gas tank was a limiting factor and a 3.3 gallon tank was offered. The riding position was cramped, while the carbs projected on the right and the hot exhaust on the left.
The 1983 XR-1000 delivered what it promised, but it was expensive at $7,000 at a time when the XLX Sportster went for $4,000. The dull gray paint hurt sales and the 1,000 XR-1000s built in 1983 were mostly discounted, while 5,000 XLX Sportsters found buyers. In 1984 the XR-1000 got a black and orange factory paint job, but only 700 bikes were built. Most sold later at a discount.
In many regards the XR-1000 is the equivalent of a classic muscle car. If you don’t understand what it does, you won’t see the point. But if you understand Lucifer’s Hammer, everything else just looks like a nail.