| Quick Specs: Honda XL 500 S (PD01) | |
|---|---|
| Production Years | 1979–1981 |
| Engine Type | Single-cylinder OHC, 4-valve |
| Oil Capacity | 1.7 L (SAE 10W-40) |
| Spark Plug | NGK DR8ES-L |
| Front Wheel | 23-inch (3.00-23) |
| Electrical System | 6V (6N4-2A-4) |
The 1979 Honda XL 500 S (PD01) remains a landmark in dual-sport history, not merely for its robust 498cc thumper engine, but for a specific engineering gamble: the 23-inch front wheel. Designed to roll over obstacles with the ease of a modern 29-inch mountain bike, this oversized front end was Honda’s solution to off-road stability before long-travel suspension geometry was fully perfected. While it made tire replacements a challenge for future collectors, it provided the XL 500 S with a unique footprint that defined the ‘Enduro’ aesthetic of the late 70s.
Technical Engineering & Performance
At the heart of the PD01 is a four-valve, OHC single-cylinder engine featuring twin exhaust ports and a counter-balancer system to mitigate the inherent vibrations of a large-bore thumper. This engine was built for torque, delivering power linearly across the RPM range, making it as capable on fire roads as it was on urban commutes. The frame is a semi-double cradle design, providing the necessary rigidity to handle the leverage exerted by that massive front wheel.
Maintenance Guide: Keeping the Legend Alive
Maintaining a PD01 requires attention to its specific vintage requirements, particularly its electrical and lubrication systems.
Lubrication and Fluids
The XL 500 S utilizes a wet-sump system. For optimal protection of the overhead cam and integrated gearbox, use 1.7 liters of SAE 10W-40 oil meeting API SE or SF standards. Modern synthetic oils are acceptable, provided they are rated for wet clutches to prevent slippage.
Tires and Pressures
The tire configuration is the most distinct aspect of this model:
- Front: 3.00-23 4PR (1.5 bar / 21 psi)
- Rear: 4.60-18 4PR (1.5 bar / 21 psi Solo; 2.0 bar / 28 psi Passenger)
Ignition and Electrical
The PD01 operates on a 6-volt electrical system, powered by a 6N4-2A-4 battery. This system is notoriously sensitive to grounding issues, so ensuring clean contacts is vital. For ignition, the NGK DR8ES-L spark plug is the factory-specified component to ensure consistent combustion under varying heat loads.
MotoSpecsLab Editorial Verdict
The Honda XL 500 S is a masterclass in transitional engineering. While the 23-inch wheel was eventually phased out in favor of the industry-standard 21-inch, the PD01 remains a highly sought-after classic for its reliability and ‘unstoppable’ feel. It is a machine that demands respect for its historical significance and rewards the diligent mechanic with a visceral, mechanical riding experience.
Frequently Asked Questions (FAQ)
Q: Is it difficult to find tires for the XL 500 S?
A: Yes, the 23-inch front tire is no longer a standard size. Specialist vintage suppliers like Bridgestone or Cheng Shin occasionally produce batches, but availability can be scarce.
Q: Can I upgrade the 6V system to 12V?
A: While possible with aftermarket kits, it requires replacing all bulbs, the battery, the regulator/rectifier, and the flasher relay. Many purists recommend maintaining the 6V system for historical accuracy.