Carby New carb-engine sputters mid throttle

[Butch]

My son had this spare carb that I think was off a Japanese dirt bike. I decided to try it on my 70cc 2 stroke. A couple modifications and it was on. It runs great at low and high throttle but sputters at mid throttle. I'll probably have to to move the needle clip up or down and see if that will help with the mid throttle sputter. Any other suggestions? The best part about this carb is I no longer get the fuel drips on the bottom of the float bowl. The needle has rubber on the tip so it seams to seal better.

 

[Guest]

SWEET! What kind/size is that?
Yep, the midrange will require the needle to be adjusted. If it spits and cuts out then the clip will have to go down (richer) if it sputters and loads up, then go leaner.

I feel a wave of "conversions" coming on......

 

[Butch]

The motor is a 70cc from dax. The carb is a ZhengSheng designed in Japan. My son had it for a spare for a 150cc dirt bike. I'll try a leaner setting tomorrow and see if that takes care of the sputtering. Thanks for the advice.

 

[Guest]

Got it, a Chinese copy of a Japanese carb.
What size is it? In millimeters?

 

[Butch]

The opening on the engine end is 19mm and the choke end is 23mm. A little bit more than the stock carb. The jet needle is the same size as the stock and the fuel bowl looks like it holds about twice as much fuel.

 

[trader]

I tried using google to locate the ZhengSheng carb designed in Japan but had no luck. Do you know where I can get one? Thanks

 

[Butch]

Sorry trader, I have no idea where my son purchased the carb. He had it sitting on a shelf in his garage for quite a while and probably doesn't remember himself where he got it from.

 

[Mattixization Rider]

I see those carbs on ebay all the time