| Feature | Specification |
|---|---|
| Production Years | 1987-2004 |
| Engine Type | 1360cc, 45° V-Twin, SOHC |
| Engine Oil | SAE 10W-40 API SF/SG JASO MA (4.3 L) |
| Front Tire | 110/90-19 62H |
| Rear Tire | 170/80-15 M/C 77H |
| Tire Pressure (F/R) | F: 2.0 bar / R: 2.0-2.5 bar |
| Battery | YB16B-A1 |
| Spark Plug | NGK DPR8EA-9 |
The Suzuki VS 1400 Intruder, specifically the VX51L designation, holds a unique place in motorcycling history as the machine that proved Japanese manufacturers could master the ‘soul’ of the American cruiser. Unlike its contemporaries, the VS 1400 featured an offset-crankpin design, which allowed Suzuki to achieve the iconic 45-degree V-twin aesthetic while maintaining primary balance, a feat of engineering that balanced character with mechanical longevity.
Engineering Overview
The heart of the VX51L is its 1360cc air/oil-cooled power plant. Suzuki utilized their proprietary SACS (Suzuki Advanced Cooling System) for the rear cylinder—a critical inclusion given the rear cylinder’s limited airflow in the tight V-configuration. The SOHC, 3-valve-per-cylinder head design was chosen to optimize low-end torque, peaking at approximately 113 Nm, making it one of the most capable ‘stump-pullers’ of its era.
Maintenance & Service Specifications
Maintaining the VS 1400 requires attention to its specific fluid and electrical needs. The engine capacity is notably large for a motorcycle, requiring 4.3 liters of 10W-40 oil. It is imperative to use oil meeting JASO MA standards to ensure the wet clutch does not slip under the high torque loads.
Ignition and Electrical
The VX51L uses a dual-plug system in earlier iterations, but the standard specification for the main spark is the NGK DPR8EA-9, gapped to 0.8-0.9mm. Power is supplied by a high-capacity YB16B-A1 battery, which is necessary to overcome the high compression of the large-bore pistons during cold starts.
Chassis and Drive
The shaft drive system on the Intruder is virtually maintenance-free compared to chain drives, but the final gear oil should be inspected periodically. For handling, tire pressure is critical: the front 19-inch wheel requires 2.0 bar (29 psi), while the rear 15-inch balloon tire must be adjusted between 2.0 bar for solo cruising and 2.5 bar when carrying a pillion or luggage.
Expert Verdict
The Suzuki VS 1400 Intruder is a masterclass in ‘Simple Engineering.’ By avoiding liquid cooling, Suzuki created a clean, lean silhouette that remains popular among customizers and purists today. For the owner, the VX51L offers a robust platform that, when maintained with the correct lubricants and spark timing, is capable of exceeding 100,000 kilometers with ease.