Calling All SU Experts

The fuel level is supposed to be 4 mm lower in the front carb float bowl, but that's not it, right?

There's a couple of things I've noticed that might help or not. A float can get hung up on the side of a bowl, depending on how it sits.  That can make it stick closed or possibly open. Can be fixed by rubbing the area of the float that hits the side of the bowl with sandpaper.

Also, especially with the new type float valves with the thinner, more wobbly pins, if the pin doesn't contact the float tang at 90 degrees it can wobble forward and jam against the tang when the float comes up, so the valve doesn't open. Fix by flattening the tang so it hits the pin at 90 degrees.

The red straw from a can of carb cleaner will fit through the vent on the float bowl lid so it sits on top of the float. Using that, sometimes you can tell if the float is sticking, and approximately how much gas is in the bowl.