| Model | Harley-Davidson XLCR CAFE RACER – 77-XLCR |
|---|---|
| Production Years | 1977-1979 |
| Engine Oil | HD Sunray 75 (Grade 50) / HD 105 (Grade 60) (2.84 L) |
| Tires (F/R) | F: 3.25-19 / R: 4.00-18 |
| Tire Pressure | F: 26 psi / R: 28-32 psi |
| Battery | 66006-70 (YB16L-B) |
| Spark Plug Gap | 0.025–0.030 in |
The Harley-Davidson XLCR stands as a radical departure from Milwaukee’s traditional cruiser lineage. A unique historical highlight of this machine is that it was the personal passion project of Willie G. Davidson, who sought to blend American V-twin power with the aesthetics of the European cafe racer movement. It was the first production Harley-Davidson to feature cast Morris Mag wheels and a distinctive “Siam-styled” 2-into-2 blacked-out exhaust system, making it a stark visual anomaly in the 1977 showroom.
Engineering & Design Philosophy
At its heart, the XLCR utilized the 1000cc (61 cu in) Ironhead Sportster engine, but housed it in a frame inspired by the legendary XR750 flat-tracker. This gave the XLCR a more aggressive geometry than the standard Sportster of the era. The bike featured triple disc brakes—a rarity for Harley at the time—and a bikini fairing that defined its silhouette. Despite its striking appearance, the XLCR was produced in limited numbers (approximately 3,100 units), making it one of the most collectible AMF-era motorcycles today.
Maintenance Guide & Technical Specifications
Lubrication System
The XLCR relies on a dry-sump lubrication system. For optimal engine longevity, MotoSpecsLab recommends using HD Sunray 75 (Grade 50) or HD 105 (Grade 60) straight-weight mineral oil. The total capacity is 2.84 Liters. Because these engines lack modern cooling, maintaining high-quality oil is critical to preventing thermal degradation of the top-end components.
Tires and Chassis Setup
The XLCR runs on a 19-inch front and 18-inch rear wheel configuration. Correct inflation is vital for the handling characteristics of this vintage frame:
- Front (3.25-19): 1.79 bar (26 psi)
- Rear (4.00-18): 1.93 bar (28 psi) for solo riding; 2.21 bar (32 psi) for duo.
Using modern compound tires in these vintage sizes can significantly improve the lean-angle confidence of the XLCR.
Electrical and Ignition
The electrical system is powered by a 66006-70 (YB16L-B) battery. For the ignition system, ensure you are using HD No. 4-7 spark plugs. The gap must be precisely set between 0.025–0.030 inches to ensure consistent combustion in the high-vibration Ironhead environment.
Editor’s Verdict
The XLCR was a machine ahead of its time. While it wasn’t a commercial success in the late 70s, its influence on the modern “Sportster S” and the custom cafe racer scene is undeniable. For the collector, it offers a visceral, mechanical riding experience that modern bikes simply cannot replicate. Proper adherence to the straight-weight oil requirements and ignition timing is the key to keeping this piece of history on the road.