The Yamaha RD 500 LC (47X) holds the distinction of being the world’s first production motorcycle to feature a liquid-cooled V4 two-stroke engine, a direct engineering descendant of the YZR500 OW61 factory racer piloted by Kenny Roberts. Unlike its competitors, the RD 500 LC utilized a complex dual-crankshaft design, making it a pinnacle of 1980s mechanical ambition.
| Specification | Data |
|---|---|
| Production Years | 1984 – 1986 |
| Engine Type | Liquid-cooled, 2-stroke, V4 (50-degree) |
| Transmission Oil | SAE 10W-30 Type SE / JASO MA (1.0 L) |
| Front Tire | 120/80-V16 (60V) |
| Rear Tire | 130/80-V18 (66V) |
| Battery | YB5L-B (12V) |
| Spark Plug | NGK BR9HS (Gap: 0.6–0.7 mm) |
Technical Overview: The GP Replica Reality
The 47X variant, primarily marketed in Europe and Oceania, represents the purest expression of Yamaha’s race-to-road philosophy. The heart of the machine is its 499cc V4 engine, which utilizes the Yamaha Power Valve System (YPVS) to manage a broad powerband. The unique layout features two separate crankshafts geared together, with the front cylinders using crankcase induction and the rear cylinders using piston-reed induction—a configuration necessitated by the tight packaging of the V4 architecture.
Maintenance & Service Guidelines
Maintaining a high-strung V4 two-stroke requires precision and adherence to factory specifications to ensure longevity and performance.
1. Lubrication System
While the engine utilizes Autolube injection for combustion, the transmission requires a high-quality SAE 10W-30 (JASO MA) oil. Total capacity is 1.0 Liter. Given the shear forces within the gearbox, annual changes are recommended regardless of mileage.
2. Ignition and Electrical
The 47X demands a consistent spark across all four cylinders. Use NGK BR9HS plugs, ensuring the gap is set strictly between 0.6 and 0.7 mm. The electrical system is supported by a YB5L-B battery; maintaining a full charge is critical for the operation of the YPVS servo motors during the startup cleaning cycle.
3. Tires and Handling
The RD 500 LC features a period-specific 16-inch front wheel designed for quick turn-in. To maintain the intended geometry, use a 120/80-V16 at the front and a 130/80-V18 at the rear. Recommended pressures for optimal carcass deformation are 2.0 bar (28 psi) front and 2.3 bar (32 psi) rear.
The MotoSpecsLab Verdict
The Yamaha RD 500 LC (47X) is not merely a motorcycle; it is a mechanical artifact from the peak of the two-stroke era. While maintenance requirements are higher than contemporary four-stroke machines, the reward is a power delivery and sensory experience that remains unmatched in the modern market. For the collector or enthusiast, preserving the 47X requires a commitment to using period-correct specifications and high-grade lubricants.