Post by kirah65 on Sept 29, 2021 17:29:47 GMT -5
Hi so im looking for some advice on my kymco zx fever 50cc not 100% on the year as i got it used but my guess is around early to mid 2000s.
The initial 0-10 ish km/h is pretty slow especially on a cold start this is not such a big deal.
However 10-35ish km/h acceleration is fantastic problem is anything above 35 is painfully slow unless down hill where it reaches around 50ish km/h easily.
So good acceleration between 10-35ish once it hits 35 its almost like its starting to brake and the sound its making is changes to a deeper humming sound.
So my first thought where the CDI box having a rpm limiter i swapped that for one without a limit still doing the same thing.
I made sure to get a unrestricted variator sleeve thing and some lighter weights for improved acceleration changed from 7.5g to 6g but it only improved the 10-35km/h range anything above that is still painfully slow.
i also made sure to change to a more open air filter a Doppler air filter Venturi as well as a unrestricted exhaust pipe its a Tecnigas Silent-Pro without the restrictions they ship with.
So now im considering if its ether the exhaust pipe being slightly too restricted cause its the " silent " version as i wanted to get something that looks like as close to stock as possible.
Or something is not right with the carburetors fuel to air mixture or i need a different sized fuel injection nozzle or its simply too small.
Problem is im not really comfortable working with carbs and i have no idea what kind of carb i would need to get if it needs to be replaced.
As i don't want it to go all that much faster then around a top speed of 50-60km/h is pretty much the sweet spot for the amount of speed i need for my daily use i just want it to get there at a decent phase and preferably not needing a downwards hill to get it there.
Any advice would be greatly appreciated.
The initial 0-10 ish km/h is pretty slow especially on a cold start this is not such a big deal.
However 10-35ish km/h acceleration is fantastic problem is anything above 35 is painfully slow unless down hill where it reaches around 50ish km/h easily.
So good acceleration between 10-35ish once it hits 35 its almost like its starting to brake and the sound its making is changes to a deeper humming sound.
So my first thought where the CDI box having a rpm limiter i swapped that for one without a limit still doing the same thing.
I made sure to get a unrestricted variator sleeve thing and some lighter weights for improved acceleration changed from 7.5g to 6g but it only improved the 10-35km/h range anything above that is still painfully slow.
i also made sure to change to a more open air filter a Doppler air filter Venturi as well as a unrestricted exhaust pipe its a Tecnigas Silent-Pro without the restrictions they ship with.
So now im considering if its ether the exhaust pipe being slightly too restricted cause its the " silent " version as i wanted to get something that looks like as close to stock as possible.
Or something is not right with the carburetors fuel to air mixture or i need a different sized fuel injection nozzle or its simply too small.
Problem is im not really comfortable working with carbs and i have no idea what kind of carb i would need to get if it needs to be replaced.
As i don't want it to go all that much faster then around a top speed of 50-60km/h is pretty much the sweet spot for the amount of speed i need for my daily use i just want it to get there at a decent phase and preferably not needing a downwards hill to get it there.
Any advice would be greatly appreciated.
