GY6 Carb Upgrade from 24mm to 26mm ?


New Member
Mar 8, 2017
United Kingdom
Do I have 50cc GY6 that is currently stock, It rubs and have ridden it around but the moment you give it some decent gas and then let it idle again it tends to try and die I have adjusted the idle screw so it ran a little better but it still won't run properly after I give it some gas.

I have heard that the 24mm Carbs that come stock with the GY6's are pretty bad and read that a 26mm solves most of peoples problems.

Is there anything anyone can think of that could fix it ?

Also what makes a standard carb different from a performance carb other that the 24mm vs **mm (e.g 26mm)

Thanks Drew


Nov 3, 2015
Nova Scotia
Your problem, "rough idle when returning from run position",
tends to be be from a mixture imbalance, rich or lean, of either the high speed or low speed circuit. I don't know your carb, but typically the idle circuit is not adjustable on most of these small carbs. If it has a needle metering rod, and it accelerates well, I would try lowering the needle (raise the clip) first and see if it improves.

If the carb is the bottleneck in the system, putting a larger one on will make more power. If the carb is not the bottleneck, typically a larger carb will make it work worse. Considering I use a 26mm carb on a 240cc engine to make 35hp, I would say a 24mm carb is too big for a 50cc engine as is.

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