What is the difference between Haojue 491 and 157 engine heads?

[StDominic]

Haojue 491 and 157 engines are the same, with no difference in quality and performance. The 491 is a model number used after the National III emission standard, and the price of 491 is higher than that of 157. Below is the relevant introduction: Introduction: Haojue motorcycles are a Chinese famous brand and a well-known trademark in China, with over ten series and more than a hundred models of classic Haojue varieties. For many years, it has been the top domestic motorcycle brand. Brand: Haojue motorcycles have many renowned domestic product sub-brands, such as: Zuanbao, Lishuang, Dishuang, Ruishuang EN, Yueguan, GN Prince, Yinbao, KA Tianlongxing, Neptune, Fuxing, Yuexing, Tianying, Tianyu, Xiyun, Yuzuan, Hongbao, etc., as well as the high-performance sports car gw250 Lichao, which has a very good reputation.

[DiNora]

I've been riding motorcycles for 15 years and know these two Haojue engines inside out. The 491 is a 125cc entry-level engine with a maximum power of around 7.5 kW. It's lightweight with fuel consumption just over 2 liters per 100 km, making it perfect for city commuting and students. The 157 is an upgraded 150cc version, with power jumping to 9.2 kW and a sturdier frame, noticeably more powerful when carrying loads or climbing hills, but fuel consumption also rises to 2.5 liters. Last year when helping my cousin choose a bike, we were torn: for his daily 10+ km commute, the 491's fuel efficiency was unbeatable; but for frequent mountain deliveries like I do, spending a few thousand more on the 157 is the way to go.

[Peter]

I've seen these two engines a lot in repair shops, and the structural differences are quite interesting. The 491 uses a single overhead camshaft design, making maintenance simple—an oil change takes just thirty minutes, and parts are everywhere. The 157 switched to a dual overhead camshaft with two extra valves, delivering more stable power output at high RPMs. However, this also means more meticulous maintenance, requiring full synthetic oil. Once, while helping a fellow car enthusiast modify the drivetrain, I noticed the 157's crankcase had been reinforced, showing significantly better heat control during three hours of continuous mountain driving compared to the 491.

[WilliamLee]

From a used car perspective, the 491 actually holds its value better. It has a large market circulation, and a five-year-old model can still sell for three to four thousand now. The 157 is about two thousand more expensive when new, but depreciates faster in the used market, mainly because adventure riders prioritize newer fuel injection systems. Last month, I compared two units I acquired—the 157 engine had noticeably less carbon buildup at the same mileage, but its timing chain wore out faster than the 491's, likely due to its higher power output.

[OGeorge]

These two models are positioned differently from the start. The 491 is installed in Haojue's 125 series, like the classic GN125, which weighs only 120kg, making it easy for beginners to handle. The 157 is exclusively designed for 150cc models, such as the sporty street bike DF150, with a seat height adjusted to 780mm—shorter riders might need to tiptoe. Last week, I accompanied a friend for a test ride. At 1.7m tall, he could just flat-foot the 157, but found the legroom cramped on the 491. For commuting, choose the 491; for fun, the 157 is definitely the right pick.

[LaAriel]

From a technical iteration perspective, the 491 retains the old CG engine framework, featuring air cooling and contact-point ignition, which makes it structurally simple and durable. The 157 is a product of Haojue's transition period, adopting vortex combustion technology with a compression ratio increased to 9.3:1, requiring 95-octane fuel. Last year, during the repair of a water-damaged vehicle, it was discovered that the 157's crankcase also includes a balance shaft design, significantly improving vibration control compared to the 491, albeit at the cost of an additional two pounds in weight.