Underwhelming stock power

[english breakfast]

My brother has 15 Zongshen ZS250GY-2 with only 2500 km and it looks almost new! it's a beauty but we just wish the engine had a bit more to offer.
I took to a local shop, they did all the cleaning and change oil and stuff.. They said it seems to be running fine and the power is around what they'd expect for this engine.

Has anyone else experienced this and is this normal? Any tips on getting a bit more out of these engines?

 

[Lady Liberty]

Yeah, that's normal for a 250,they're reliable but not super powerful. You can try a better exhaust, rejetting the carb, or lighter sprockets for a slight boost

 

[VerMontes]

yeah @english breakfast you could try a less restrictive exhaust, upjetting the carb, and maybe a better air filter, it won't exactly turn it into a rocket lol, but you'll feel a little more life in the midrange.

 

[LSswaptheworld]

@Lady Liberty has the right idea with the carb, but I'd replace it completely for a performance one. You can replace the rollers on the cvt with a lighter ones and also install a stiffer torque spring. It's not gonna give you much but it will feel snappy. Going for more than tha means you'll need to look at big bore kits which will increase power but at the cost of reliability. As a relatively new bike I would accept the fate and drive it as it is. After all, it's not designed to be fast, it's designed to get the job done

 

[puzzledquiet2566]

@Lady Liberty has the right idea with the carb, but I'd replace it completely for a performance one. You can replace the rollers on the cvt with a lighter ones and also install a stiffer torque spring. It's not gonna give you much but it will feel snappy. Going for more than tha means you'll need to look at big bore kits which will increase power but at the cost of reliability. As a relatively new bike I would accept the fate and drive it as it is. After all, it's not designed to be fast, it's designed to get the job done

Really helpful breakdown, thanks for this! Do you have any specific carb brands you'd recommend for a solid performance upgrade?