Make sure the float pin moves freely when you move the float up and down. If not then it's probably got some rust buildup on the sides. Sand it off or scrape it off with a utility blade and make sure the rubber tip is in good condition.
Your carb is probably different but the float valve works the same way as this one:
Last Edit: Nov 14, 2017 12:59:14 GMT -5 by 90GTVert
I've spent the past few days researching how to set the float height on my carb properly. I received a new Kei Hin carb and the float bowl base is slanted which makes it really hard to set the float height if you don't have a carb that has the edge parallel to the floats themselves..
From what I can tell, there are 2 flat bases that you can take the measurements from. One on each side of the carb for each float side. If the carb is sitting upside down on a flat surface on the diaphram cover, the float line should pretty much be parallel with the top of the diaphram cover itself. This puts the float line at approximately 10mm from the flat bases and approximately 19mm from the bottom of the float (upside down) to the flat bases. Make sure to have the tang just touching the pin in the float valve. If you set it upside down, it will actually push the pin in a bit and skew the measurements. I had to lean the carb a bit to keep it from pushing the pin in and use a set of digital calipers to set it right.
The only thing I can find anywhere I search is that the float level needs to be set to 19mm and that was a long shot to find.
Last Edit: Nov 14, 2017 12:59:40 GMT -5 by 90GTVert
2007 Chinese GY6 139QMB 50cc (Bumblebee) - 100cc Big Bore Kit - Big Valve Head (23mm & 20mm Valves) - A9 Performance Cam - Performance Racing CDI (Blue) - 18mm Kei-Hin Carb - #90 Main Jet - K&N Style POD Air Filter - Gates Powerlink Belt - DLH Performance Variator - 8 Gram Sliders - 1K Hoca Contra Spring FYI - You don't always need a bigger carb to get better performance!