Yamaha SR 250 SE – 3Y8 Specs: Oil Capacity & Tire Pressure

Historical Context & Engineering Highlight

The Yamaha SR 250 SE (3Y8) holds a unique place in motorcycling history as one of the first factory-produced ‘Special Edition’ (SE) models that successfully translated the custom-cruiser aesthetic to a small-displacement platform. Unlike its competitors, which often felt like scaled-down versions of larger bikes, the SR 250 was engineered with a ‘monoblock’ simplicity. Its single-cylinder engine was remarkably over-engineered for its class, featuring a counter-balancer that made it one of the smoothest-running 250cc singles of the early 1980s—a design philosophy that later influenced the legendary SR400 and SR500 series.

Technical Deep Dive

The heart of the 3Y8 is its air-cooled, Single Overhead Cam (SOHC) engine. It was designed for torque efficiency rather than top-end speed, making it an ideal urban commuter. The 16-inch rear wheel combined with the 19-inch front provides the classic ‘low-rider’ stance while maintaining stable handling characteristics. The inclusion of a disc brake at the front was a premium feature for 250cc bikes in 1980, significantly improving safety over the drum-only setups of the era.

Maintenance Protocols

Lubrication System

To maintain the longevity of the SOHC valvetrain, MotoSpecsLab recommends adhering strictly to the 1.4-liter capacity. Using SAE 20W-40 is critical as it provides the necessary viscosity for air-cooled temperature fluctuations. Modern synthetic blends are acceptable, provided they do not contain friction modifiers that could interfere with the wet clutch system.

Chassis and Tires

Handling precision on the SR 250 SE is highly sensitive to tire pressure. Maintaining 1.75 bar (25 psi) in the 3.00-19 front tire and 2.0 bar (28 psi) in the 120/90-16 rear tire is essential to prevent ‘hunting’ during cornering. Given the age of these machines, inspect the sidewalls of the 16-inch rear tire frequently, as this size can be prone to heat-related stress.

Electrical and Ignition

The YB12A-A battery serves a relatively simple electrical system. However, the NGK DR8ES-L spark plug should be inspected every 3,000 miles. A light tan color on the insulator indicates a healthy air-fuel mixture, whereas carbon fouling may suggest the Mikuni carburetor requires a needle adjustment or cleaning.

Editor’s Verdict

The Yamaha SR 250 SE (3Y8) is a masterclass in functional simplicity. For the modern collector or enthusiast, it offers an accessible entry point into vintage motorcycling with a robust parts supply and straightforward mechanical layout. It remains a benchmark for how a lightweight cruiser should be balanced.

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