What does motorcycle stroke mean?
2 Answers
Motorcycle strokes are divided into 2-stroke and 4-stroke, with the following specific introductions: 1. 2-stroke: A 2-stroke means that the crankshaft completes one working cycle in one rotation, which includes intake (called scavenging in 2-stroke), compression, power, and exhaust. This is the characteristic of a 2-stroke engine. 2. 4-stroke: A 4-stroke engine requires two rotations of the crankshaft to complete one working cycle, consisting of intake, compression, power, and exhaust. 2-stroke engines do not have valves and use scavenging ports on the cylinder liner for intake. 4-stroke engines have valves, which are opened and closed via the camshaft driven by the timing chain (small chain) connected to the crankshaft timing gear. 2-stroke engines of the same displacement produce more power than 4-stroke engines, but 4-stroke engines are more fuel-efficient.
I've been riding motorcycles for over a decade, and the term 'stroke' might sound technical but it's actually quite simple to understand. It refers to the number and manner of piston movements within the engine cylinder. There are two main types of motorcycle engine strokes: two-stroke and four-stroke. A two-stroke engine completes one working cycle with just two piston movements - combining intake and compression into one step, and expansion and exhaust into another. The advantages are simple structure, light weight, and quick acceleration, making it particularly suitable for off-road or small vehicles. However, it has significant drawbacks like higher fuel consumption, loud noise, excessive smoke emissions, poor environmental performance, and troublesome maintenance. The four-stroke engine requires four piston movements divided into four steps: intake, compression, expansion, and exhaust, each performed once. It operates smoothly, is fuel-efficient, durable, and suitable for street bikes, sports bikes, and modern motorcycles. I usually ride four-stroke bikes more often - while not as powerful as two-strokes, they're more reliable and cost-effective. From my long riding experience, two-stroke engines are commonly found in older bikes, while modern new motorcycles predominantly use four-stroke engines because they're cleaner and safer.
