The Harley-Davidson XR1000 aims to capture the success of the XR750…

Harley-Davidson XR1000

With Ian Fallon

Back in the early 1980s, Harley-Davidson was struggling. In an era dominated by Japanese multi-cylinder engines with twin overhead camshafts, 4-valve heads and liquid cooling, Harley still offers V-twin, two-valve, air-cooled engines. old fashioned gas.

Harley acquired itself from AMF in 1981 and immediately scrapped the revolutionary liquid-cooled Nova V-four prototype that AMF was developing. This left them with nothing new in development so in the interim, Willie G. Davidson proposed a hybrid performance model, essentially a Sportster with an XR-based engine. for racing cars. With a combination of XLX Sportster and modified XR750 parts, the XR1000 is theoretically an easy and inexpensive solution to Harley’s immediate dilemma.

The XR1000 engine is built around the bottom of the original XLX Sportster, with distinctive barrels and cylinder heads. Since the extended XR750 aluminum cylinders were too small to fit in the XLX housing, new 81mm iron cylinders were required, with new aluminum pistons and connecting rods.

These taper and blade rods (one running inside the other on the crankshaft), are bolted to the XLX single-shot crankshaft, with four “Q” cams raised slightly below the right cover.

So the taller engine can fit into the Sportster frame, the new cylinders are 12.7mm shorter and improved via bolts to the cylinder head instead of the separate bolt arrangement of Standard XLX Sportster. They also include more fins to improve heat dissipation.

Dick O’Brien, head of HD’s renowned racing division, was tasked with developing the XR1000 engine. Instead of the XLX cast iron cylinder head with a wide 90-degree valve angle, the XR1000 cylinder head is based on the XR750.

These are aluminum grades with a shallower 68-degree valve angle. This allows for a shallower combustion chamber and flat pistons, even with a 9:1 compression ratio. The XR1000 requires a new cylinder head with slightly larger valves to allow for a 998cc capacity increase.

After basic machining in Milwaukee, the heads are sent to traffic specialist Jerry Branch in California. Branch performed the transfer and polishing, lightened the twin valve springs, and fitted the titanium collars and retainers.

As on the XR750, the rear cylinder head is reversed. So, instead of the usual central Keihin carburetor, the carburetor is a pair of 36 mm PHF Dell’Orto pump carburetors, both located on the right side of the engine and wearing large K&N air filters. .

Just like the XR, the exhausts are on the left side of the engine, curving sharply towards the top of the main box before ending in a pair of speakers. Power is up 10 hp over the XLX, to 70 hp at 5,600 rpm.

This is transmitted through the usual triplex primary chain and multi-disc wet clutch and a four-speed Sportster transmission. Considering the XR1000 is considered a street racer, fifth gear would be a welcome addition but that was beyond the realm of possibility at the time.

This engine has been bolted to the XLX frame. Introduced a year earlier, the XLX features modern-looking welded steel pipes rather than the individual cast pipes of the past. But with the engine bolted firmly in place, vibration was an issue due to the unbalanced 45-degree V-twin.

The suspension is also very basic compared to other 1000 cc sport bikes; Showa 35mm front fork and Showa rear shock absorber are both non-adjustable.

Steering is predictably slow with the steering wheel extending 29.7 degrees, trailing 114 mm, and the wheelbase 1,524 mm long. The dirt track roots are evident in the choice of 19- and 16-inch wheels, although a sportier 18-inch rear wheel is also available as an option.

The XR1000 is also the first Harley to feature a dual disc front, with 292 mm discs designed in the style of factory XR750 racers. Although the brake calipers are just one piston, this brake system is the best for a Harley.

Not the most practical street bike, the XR1000 weighs 218 kg dry and the small 8.5 liter fuel tank offers a range of 180 km. Powerful engine performance, XR1000 reaches speeds of about 200 km / h but is extremely uncomfortable.

Coupled with shrill vibrations, the 737 mm low saddle height and front-mounted Sportster footpegs lead to hot carburetors and exhausts that dirty the rider’s feet.

Initially only available in the US, the XR1000’s $7000 price tag turned out to be a major drawback. When a similar-looking XLX Sportster sells for $4,000, it simply isn’t a good value.

Gray was initially considered unattractive but in its second year the XR1000 was painted in the traditional Harley orange and black tones. Harley built 1,000 XR1000s in 1983, but many of them remained unsold.

Over 700 XR1000s were built in 1984, but most were subsequently discounted and the model was discontinued. Harley also offers a racing kit with 10.5:1 pistons, hotter cams, 38mm carburetors and a non-sealing exhaust system that delivers an extra 20hp.

Evil and unrefined, the XR1000 is a mystery. As a replacement racer, a production road bike created by a dirt road racer, it has compromised functionality. But the XR1000 isn’t just a collection of parts.

The Jay Springsteen part whizzing past the dusty bend of the Indianapolis Mile and the bulging biceps of a hot Sportster.

This is a motorcycle with a rippled pulse that you can feel through your arms, legs, butt, and heart. The XR1000 is unique and epitomizes the essence of the Harley-Davidson experience.