| Specification | Details |
|---|---|
| Production Years | 1981-1994 |
| Engine Type | 49cc, 2-Stroke, Air-Cooled |
| Transmission Oil | 0.6 L – SAE 10W-40 JASO MA |
| Tire Size (Front/Rear) | 2.50-18 4PR / 2.75-18 4PR |
| Tire Pressure (F/R) | 1.5 bar (21 psi) / 1.8 bar (25 psi) |
| Battery Type | 6N4-2A-4 (6V System) |
| Spark Plug | NGK B8ES |
A unique engineering highlight of the Kawasaki AR 50 was its pioneering use of the Uni-Trak mono-shock rear suspension. While its competitors were still largely utilizing twin-shock setups for small-displacement mopeds, Kawasaki adapted their professional motocross and GP racing technology to this 50cc platform, providing superior handling and a “big bike” aesthetic that defined a generation of teenage riders.
Engineering Overview
The AR 50, specifically the AR050A through C variants, was designed to bridge the gap between utility mopeds and sport motorcycles. Powered by a high-revving 49cc air-cooled two-stroke engine, it utilized a disc brake at the front—a rarity for the 50cc class in the early 1980s. The frame was a lightweight tubular steel semi-double cradle, designed to withstand the vibrations inherent in a high-strung two-stroke single.
Maintenance Guide
Lubrication and Fluids
For the transmission, the AR 50 requires exactly 0.6 Liters of SAE 10W-40 engine oil. We recommend using a JASO MA certified oil to ensure proper clutch engagement and prevent slippage. As a two-stroke machine, it utilizes an oil injection system; always ensure the separate 2-stroke oil tank is topped with high-quality synthetic or semi-synthetic 2-stroke oil.
Ignition and Electrical
The electrical system operates on a 6V architecture, powered by a 6N4-2A-4 battery. Maintenance of the ignition system is straightforward: the factory specifies the NGK B8ES spark plug. Gapping should be checked periodically to ensure consistent combustion, especially given the tendency of small two-strokes to foul plugs during low-speed city riding.
Chassis and Tires
The AR 50 sits on 18-inch wheels, which contribute to its stable, motorcycle-like handling. The front uses a 2.50-18 4PR tire, while the rear utilizes a slightly wider 2.75-18 4PR. Maintaining correct pressures is critical for both tire longevity and cornering safety: 1.5 bar (21 psi) in the front and 1.8 bar (25 psi) in the rear.
MotoSpecsLab Verdict
The Kawasaki AR 50 remains a cult classic due to its over-engineered chassis and racing pedigree. For collectors and restorers, following the factory specifications for fluids and ignition is paramount to preserving the performance of the AR050A-C series. Its mechanical simplicity combined with advanced-for-the-time suspension makes it a rewarding project for vintage enthusiasts.