| Category | Specification |
|---|---|
| Model Code | L250S |
| Production Years | 1978-1981 |
| Engine Type | 248cc Single-Cylinder, 4-Valve, OHC |
| Oil Specification | 1.3 L – SAE 10W-40 API SE or SF |
| Tire Size (Front) | 3.00-23 4PR |
| Tire Size (Rear) | 4.60-18 4PR |
| Tire Pressure (F/R) | 1.5 bar (21 psi) / 1.5-2.0 bar (21-28 psi) |
| Battery Type | 6N4-2A-4 (6-Volt) |
| Spark Plug | NGK DR8ES-L |
At MotoSpecsLab, we recognize the Honda XL 250 S as a pivotal moment in dual-sport history. While many motorcycles of the late 1970s were struggling to find a balance between street legality and dirt performance, Honda introduced a radical engineering choice: the 23-inch front wheel. This oversized rim was designed specifically to roll over obstacles that would deflect a standard 21-inch wheel, providing the XL 250 S with unmatched stability in technical terrain during its era.
Engineering Analysis: The 4-Valve Evolution
The L250S power plant was a significant departure from its predecessors. It featured a sophisticated four-valve cylinder head and twin counter-balancers to reduce the inherent vibration of a large single-cylinder engine. This made the XL 250 S one of the smoothest ‘thumpers’ on the market, allowing for longer road transits without the rider fatigue common in the 250cc class.
Maintenance Essentials
Lubrication System
The Honda XL 250 S utilizes a wet-sump lubrication system. For optimal protection of the overhead cam and the integrated 5-speed gearbox, we recommend 1.3 liters of SAE 10W-40. Given the air-cooled nature of this engine, ensure the oil meets at least API SE or SF standards to handle the high thermal loads encountered during slow-speed trail riding.
The 23-Inch Challenge
The most critical maintenance item for the XL 250 S owner is tire management. The 3.00-23 front tire is a rare size in the modern market. Owners should maintain a pressure of 1.5 bar (21 psi) for general use. Lowering the pressure for off-road traction is common, but due to the large diameter of the rim, maintaining bead seating is vital.
Electrical System
The L250S operates on a 6-volt electrical system powered by a 6N4-2A-4 battery. This system is notoriously sensitive to grounding issues. Regular inspection of the spark plug (NGK DR8ES-L) and ensuring clean battery terminals are essential for reliable starting, as the bike relies solely on a kick-starter.
Expert Verdict
The Honda XL 250 S remains a masterpiece of late-70s engineering. Its combination of a high-revving 4-valve head and the experimental 23-inch front wheel makes it a collector’s favorite. While parts for the front end can be difficult to source, the engine’s legendary reliability ensures that with proper oil changes and valve clearances, the L250S will continue to tackle trails for decades to come.