1984–1986 Harley-Davidson Dyna/FXR Evolution 1340 (FXRDG Disc Glide)

The 1984–1986 Harley-Davidson Dyna/FXR Evolution 1340 (FXRDG Disc Glide) represents a pivotal moment in the history of the Milwaukee-based motorcycle manufacturer. This model was not just another cruiser; it was the confluence of Harley-Davidson’s most advanced chassis technology at the time and its brand-new, revolutionary V-twin engine. As a special, limited-edition model, the FXRDG Disc Glide served as a stylish flagship, showcasing the company’s successful emergence from the troubled AMF years and heralding a new era of reliability and performance.

The FXR platform, introduced in 1982, was a significant departure from traditional Harley-Davidson design. Conceived with input from Erik Buell, the frame utilized a unique system of rubber engine mounts, known as the Tri-Mount system, to isolate the rider from the V-twin’s vibrations without sacrificing chassis rigidity. This design resulted in a motorcycle that handled with unprecedented precision and stability for a Big Twin, earning it a reputation as the best-handling Harley-Davidson ever produced.

The Arrival of the Harley-Davidson Dyna/FXR Evolution 1340

The most significant update for the 1984 model year was the introduction of the 1340cc (80 cubic inch) Evolution engine. The “Evo,” or “Blockhead” as it is sometimes known, was a massive leap forward from the venerable Shovelhead engine it replaced. While retaining the classic 45-degree V-twin architecture, the Evolution engine featured aluminum cylinders and heads, which were lighter and dissipated heat far more effectively than the Shovelhead’s cast-iron components. This, combined with improved oiling, tighter manufacturing tolerances, and advanced combustion chamber design, resulted in an engine that was not only more powerful but also significantly more reliable, cooler running, and oil-tight. The arrival of the Evolution engine was a critical step in rebuilding Harley-Davidson’s reputation for quality.

The FXRDG Disc Glide

The FXRDG Disc Glide was a special edition model produced in limited numbers, specifically to celebrate the new engine. Its most distinguishing feature, and the source of its name, was its solid aluminum disc rear wheel, a design element that evoked the custom chopper scene of the era. The front wheel remained a traditional wire-spoke design.

This model was also characterized by its unique and premium features. It came with a special two-tone paint scheme, extensive chrome detailing, and a fully enclosed final drive chain. The enclosed chain was a feature designed to reduce maintenance and keep lubricant from flinging onto the polished disc wheel, though it was later phased out in favor of the cleaner belt-drive systems. The FXRDG combined the performance-oriented attributes of the FXR chassis with the aesthetic of a high-end custom cruiser, making it a highly desirable machine from the moment it was released.

Differences From Previous Models

The primary difference between the 1984 FXRDG and its immediate predecessors, the Shovelhead-powered FXRs, was the powertrain. The Evolution engine offered a smoother power delivery and a substantial increase in dependability. Riders no longer had to contend with the frequent oil leaks and mechanical issues that were often associated with the older Shovelhead design. Cosmetically, the FXRDG stood apart from standard FXR models of the same year with its exclusive disc rear wheel, premium paint, and additional chrome, positioning it as a top-tier, limited-production model. The introduction of the Evolution engine marked a clear dividing line between the old and new eras of Harley-Davidson engineering.

Specifications: 1984 Harley-Davidson FXRDG Disc Glide