| Specification | Detail |
|---|---|
| Production Years | 1988 – 1989 |
| Engine Type | 727cc Single-cylinder, SACS (Air/Oil Cooled) |
| Engine Oil | SAE 10W-40 API SF/SG (2.6 L) |
| Tires (F/R) | 90/90-21 54H / 130/80-17 65H |
| Spark Plugs | 2x NGK DPR8EA-9 |
| Battery | YB14L-A2 (12V 14Ah) |
While modern adventure enthusiasts often attribute the iconic “beak” design to European manufacturers, the Suzuki DR 750 S BIG (SR41B) was the true progenitor of this aesthetic in 1988. Beyond its visual legacy, the DR 750 BIG holds a significant engineering milestone: at its launch, it featured the largest single-cylinder engine ever fitted to a production motorcycle, a 727cc powerhouse designed to conquer the grueling Paris-Dakar Rally.
Engineering Overview: The SACS Heart
The SR41B utilizes the Suzuki Advanced Cooling System (SACS), which employs high-volume oil jets to cool the cylinder head and piston. This hybrid air/oil cooling allowed Suzuki to maintain the simplicity of a thumper while managing the immense thermal loads generated by such a massive displacement. The engine’s character is defined by massive low-end torque, though it requires precise maintenance of the twin-spark ignition system to ensure smooth combustion across the large bore.
Maintenance Guide & Technical Data
Lubrication System
For the SR41B, oil is more than a lubricant; it is a vital coolant. We recommend a high-quality SAE 10W-40 mineral or semi-synthetic oil meeting API SF or SG standards. The total capacity is 2.6 liters. Given the SACS design, keeping the oil cooler fins clean and the oil levels topped up is critical for engine longevity.
Ignition & Electrical
The DR 750 BIG utilizes a dual-plug head to ensure efficient flame propagation. Use two NGK DPR8EA-9 plugs gapped to 0.8-0.9mm. The electrical system is supported by a YB14L-A2 battery. Due to the high compression of the 727cc piston, a healthy battery and clean starter motor contacts are essential for reliable ignition.
Chassis & Tires
The SR41B rides on a 21-inch front and 17-inch rear configuration, typical for dual-sport machines of the era. For optimal handling and tire wear, adhere to the following pressures:
- Front (90/90-21): 1.75 bar (25 psi)
- Rear (130/80-17): 2.00 bar (29 psi) solo / 2.25 bar (33 psi) with passenger
MotoSpecsLab Verdict
The Suzuki DR 750 S BIG is a masterclass in late-80s Japanese engineering. It is a robust, mechanically honest machine that rewards the rider with a unique tactile experience. While its successor, the DR 800, gained more fame, the SR41B remains the pure, original “Desert Express.” For collectors and vintage ADV riders, maintaining the SR41B according to these specifications is paramount to preserving its historic performance.
FAQ
How often should I change the oil?
Under normal conditions, every 6,000 km (3,700 miles). However, if used off-road or in high-heat environments, 3,000 km intervals are recommended to protect the SACS components.
Why does it have two spark plugs?
The large cylinder bore (105mm) makes it difficult for a single spark to ignite the fuel-air mixture quickly and evenly. Dual plugs ensure more complete combustion and better throttle response.