Motorcycle Compression Ratio?
2 Answers
Motorcycle compression ratio refers to the ratio between the total volume swept by the piston from top dead center to bottom dead center plus the combustion chamber volume, and the combustion chamber volume alone. High Compression Ratio: If the compression ratio is high but low-octane fuel is used, engine knocking may occur. Knocking happens when the air-fuel mixture ignites prematurely before the spark plug fires, while the piston hasn't yet reached top dead center. This premature explosion is very harmful to the engine. Low Compression Ratio: Using high-octane fuel in a low compression ratio engine will cause the air-fuel mixture to be ignited by the spark plug before being compressed to an optimal level. This leads to incomplete combustion, increased carbon deposits, and reduced engine power.
When I was young, I bought my first motorcycle. The compression ratio refers to the ratio of the cylinder volume at the end of the compression stroke to the initial volume, such as 10:1 indicating a tenfold compression. This affects many aspects of daily riding. A higher compression ratio usually provides a stronger sense of acceleration, making it easier to ride on highways, but may result in slightly higher fuel consumption. On the other hand, a lower compression ratio makes the engine more tolerant of lower-quality fuel, offers smoother performance in stop-and-go city traffic, and reduces the likelihood of knocking. I remember the specific value can be found in the manual, and different motorcycles have varying compression ratios, with street bikes typically ranging between 9.5:1 and 11.5:1. During maintenance, it's important to use the correct oil to prevent engine overheating and extend its lifespan. In short, as an average rider, knowing this value can help you make more informed choices when refueling.
