4 min read Jul 10, 2024

YZ250-001: The Heart of Yamaha's 2-Stroke Motocross Bikes


The YZ250-001 is a legendary engine model that powered Yamaha's iconic 2-stroke motocross bikes in the 1980s and 1990s. This engine was the heart of Yamaha's motocross machinery, providing unmatched power, performance, and reliability. In this article, we'll delve into the features, specifications, and performance of the YZ250-001 engine.

Design and Features

The YZ250-001 engine is a 249cc, 2-stroke, single-cylinder powerplant that features a liquid-cooled system. It has a bore and stroke of 66.4mm x 72mm, respectively, and a compression ratio of 6.6:1. The engine is equipped with a 38mm Mikuni carburetor and a five-port exhaust system.

One of the notable features of the YZ250-001 is its revolutionary cylinder design, which utilizes a patented Yamaha Power Valve System (YPVS). This system allows for better power delivery and increased performance across the rev range. The engine also features a lightweight aluminum cylinder and a ceramic-plated cylinder bore for improved durability and reduced friction.


The YZ250-001 engine is known for its exceptional power output, producing around 55 horsepower at 12,000 rpm. Its torque output is equally impressive, peaking at around 35 ft-lbs at 11,000 rpm. The engine's power delivery is characterized by a strong low-end punch and a smooth, linear power curve.

The YZ250-001's performance is further enhanced by its lightweight design, which results in a dry weight of approximately 220 pounds. This, combined with its impressive power output, makes it an ideal engine for motocross and off-road applications.

Reliability and Maintenance

The YZ250-001 engine is renowned for its reliability and durability. Its liquid-cooled system helps to reduce engine temperatures, while its ceramic-plated cylinder bore and aluminum cylinder reduce wear and tear. The engine's five-port exhaust system also helps to minimize engine braking and improve overall performance.

Regular maintenance is essential to ensure the longevity of the YZ250-001 engine. This includes routine checks on the spark plug, air filter, and fuel filter, as well as periodic adjustments to the ignition timing and carburetor settings.


The YZ250-001 engine is a testament to Yamaha's commitment to innovation and excellence in the motocross industry. Its impressive power output, lightweight design, and reliability make it a sought-after engine among motocross enthusiasts and collectors. Whether you're a seasoned rider or a enthusiast, the YZ250-001 engine is an iconic piece of motocross history that continues to inspire and thrill riders to this day.

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