| Quick Specs: Yamaha XT 550 – 5Y3 (1982-1983) | |
|---|---|
| Engine Type | 4-Stroke, SOHC, 4-Valve Single |
| Oil Capacity | 2.1 L (SAE 10W-30 / 20W-40) |
| Spark Plug | NGK DPR8EA-9 |
| Battery | 12N5.5-3B |
| Front Tire | 3.00-21 4PR (1.5 bar / 21 psi) |
| Rear Tire | 4.60-18 4PR (1.8 bar / 25 psi) |
The Yamaha XT 550 (5Y3) holds a significant place in motorcycling history as the platform that introduced the Yamaha Dual Intake System (YDIS). This revolutionary engineering feat utilized two carburetors—one primary and one secondary—to solve the age-old dilemma of single-cylinder engines: providing smooth low-end torque without sacrificing high-RPM breathing. By staging the intake, Yamaha created a dual-sport machine that was as capable on the highway as it was on the trails of the early 80s.
Technical Engineering Overview
The 558cc heart of the XT 550 was a departure from its predecessor, the XT 500. It featured a four-valve head and a counter-balancer to mitigate the vibrations inherent in large-capacity singles. The 5Y3 designation specifically refers to the early 1980s production run, characterized by its monoshock rear suspension (Cantilever system), which provided superior travel compared to the twin-shock layouts of the era.
Maintenance Guide & Essentials
Lubrication System
For optimal engine longevity, MotoSpecsLab recommends high-quality mineral or semi-synthetic oils. The total capacity is 2.1 Liters. Use SAE 10W-30 for cooler climates or 20W-40 for standard operating conditions. Given the air-cooled nature of the 5Y3, regular oil changes every 3,000 km are vital to prevent thermal degradation.
Ignition and Electrical
The XT 550 utilizes a 12V electrical system powered by a 12N5.5-3B battery. For the ignition system, the NGK DPR8EA-9 is the specified spark plug. Ensure the gap is set to 0.8–0.9mm to maintain consistent combustion, especially under the varying pressures of the YDIS intake cycles.
Chassis and Wheel Fitment
The XT 550 remains a staple for vintage enduro enthusiasts. Maintaining correct tire pressure is critical for handling stability. The front 3.00-21 tire should be set to 1.5 bar (21 psi), while the rear 4.60-18 requires 1.8 bar (25 psi) for standard road and light trail use. For heavy off-road applications, pressures may be adjusted slightly lower, though rim locks are recommended if doing so.
Editorial Review: The MotoSpecsLab Verdict
Performance: 4.5/5
The XT 550 was a torque monster for its time. The YDIS system effectively eliminated the ‘stumble’ often found in large-bore singles during rapid throttle opening. While slightly heavier than modern enduros, its mechanical purity and ruggedness make it a top-tier choice for collectors and vintage rally participants.
Frequently Asked Questions
Q: What oil should I use in my 1982 XT 550?
A: We recommend SAE 10W-30 or 20W-40, with a refill capacity of 2.1 liters.
Q: What is the correct spark plug gap for the 5Y3?
A: The NGK DPR8EA-9 should be gapped to 0.8mm – 0.9mm.
Q: Is the XT 550 a 6V or 12V system?
A: The XT 550 (5Y3) operates on a 12V electrical system using a 12N5.5-3B battery.