carb float level and other carb issues

[nogig]

I got a replacement carb from BGF for my bike and put it on and it was only ruinning about 16 mph upon closing petcok it would increase speed to about 23 mph. took off float bowl and found float level was set verrry low so here are my questions

1. What is the proper float hieght? a recall seeing 21 mm somewhere but 21 mm measured from where?

2. why would closing the petcock improve a fuel starvation issue?


I ve built tons of carbs and such hoping the float level will cure this. also for any interested e clip is in second from top groove same as other carb was. plug is of acceptable color, fuel flow from petcock is proper. all help is appreciated

 

[GearNut]

If ya shut off the gas at the tank and she runs better, then you are effectively lowering the fuel level inside the float bowl as the engine consumes the fuel.
This leads me to believe that you have a too high of a float setting.
I don't know what kind of carb you are talking about, but as rule of thumb, I set float heights to 1/8 inch or 2mm below the gasket surface when I am repairing a mystery carb.

 

[nogig]

If ya shut off the gas at the tank and she runs better, then you are effectively lowering the fuel level inside the float bowl as the engine consumes the fuel.
This leads me to believe that you have a too high of a float setting.
I don't know what kind of carb you are talking about, but as rule of thumb, I set float heights to 1/8 inch or 2mm below the gasket surface when I am repairing a mystery carb.

it is this style carb




I had an nt on it and just bought this for cheapness

thanks for the float height spec . i cant see me trying to move it a piece at a time . also i swpaaed out my old nt needled and it didnt wor cus the new carb has a nonger needle (fuel shut off needle) anyways i guess i'll fornicate with it tomorrow