| Specification | Data |
|---|---|
| Production Years | 1980–1982 |
| Engine Oil | SAE 10W-40 (API SE/SF) – 1.5 L |
| Front Tire | 3.00-21 4PR (1.25 bar / 18 psi) |
| Rear Tire | 4.60-18 4PR (1.50 bar / 22 psi) |
| Battery | 6N6-3B (6V System) |
| Spark Plug | NGK DR8ES-L |
The Suzuki DR 400 S holds a unique place in motorcycling history as the first off-road oriented machine to utilize Suzuki’s proprietary Twin Swirl Combustion Chamber (TSCC) technology. This engineering milestone, originally developed for high-performance GSX street bikes, allowed for faster flame propagation and improved volumetric efficiency, giving the DR400S a distinct torque advantage over its contemporaries in the early 1980s dual-sport market.
Technical Overview
Positioned between the lighter DR370 and the heavy-hitting DR500, the DR400S was designed for riders seeking a balance of agility and power. Its air-cooled, SOHC four-stroke engine was praised for its reliability and linear power delivery. Unlike modern high-strung enduros, the DR400S was built with longevity in mind, utilizing robust materials that have allowed many units to remain functional over four decades later.
Maintenance Guide & Fluid Capacities
Lubrication System
For optimal engine protection, MotoSpecsLab recommends using a high-quality SAE 10W-40 motor oil. The engine requires exactly 1.5 Liters during a standard oil change. Given the vintage nature of the seals and internal components, ensuring the oil meets the API SE or SF specifications is critical for preventing clutch slippage and premature wear.
Tires and Handling
The DR400S utilizes a classic 21-inch front and 18-inch rear wheel configuration. To maintain the intended geometry and traction levels, the front tire (3.00-21) should be inflated to 1.25 bar (18 psi), while the rear (4.60-18) requires 1.50 bar (22 psi). These pressures provide the necessary compliance for trail riding while maintaining stability on paved surfaces.
Electrical & Ignition
As a product of its era, the DR400S operates on a 6-volt electrical system. The 6N6-3B battery must be kept in good condition to ensure consistent lighting and ignition performance. For the spark plug, the NGK DR8ES-L is the factory-specified component, offering the correct heat range to prevent fouling during slow-speed technical riding.
Editor’s Verdict
The Suzuki DR 400 S is more than just a vintage dirt bike; it is a testament to Suzuki’s era of rapid combustion innovation. While its 6V electronics and drum brakes are dated by modern standards, its mechanical soul remains bulletproof. It remains a highly collectible and functional piece of dual-sport history for those who value mechanical purity.