What do the numbers 428 and 420 mean for motorcycle sprockets?
2 Answers
Motorcycle sprockets 428 and 420 refer to different models of chains used for motorcycles. Introduction to motorcycle sprocket model composition: Generally, motorcycle chain models consist of two parts, separated by a hyphen. Chain model: The first part of the sprocket number represents the model, composed of three Arabic numerals. The larger the number, the larger the chain size. Each model of chain is divided into standard and heavy-duty types, with the heavy-duty type marked by the letter H after the model number. Both 428 and 420 refer to the sprocket model. Introduction to chain link count: The second part of the sprocket number represents the link count, composed of three Arabic numerals. The larger the number, the more links the entire chain contains, meaning the chain is longer. Each link count chain is divided into standard and light types, with the light type marked by the letter L after the link count.
Seeing you ask about motorcycle sprockets 428 and 420 reminds me of the common confusion I encounter during daily repairs. Those numbers are actually chain specification codes. 428 typically represents a chain with a larger pitch, around 12.7mm, used for mid-sized motorcycles around 250cc, offering high strength and durability, making it suitable for long-distance or heavy-load riding. On the other hand, 420 is a smaller chain with a pitch of about 12.0mm, commonly found on small-displacement bikes like 125cc or older models. It's lightweight and fuel-efficient but prone to loosening. Matching the sprocket size is crucial, as the front-to-rear sprocket tooth ratio affects acceleration and fuel consumption. If you ride a mid-to-large-sized bike, opting for a 428 chain is more reliable. Regularly checking the tension and applying lubricant can extend its lifespan to over 20,000 kilometers. Don’t forget, mismatched sizes can cause noise, rapid wear, or even dangerous chain breaks, so it’s best to follow the manufacturer’s recommendations.
