Fuel taps and float bowls: Gas leaking?

This question relates to a fuel tap and carbuertors on a 1979 650SR. Tap is vacuum operated, the carbs have the accelerator pump on carb body #2.

I have rebuilt the fuel tap with a repair kit from K&N. And had the carburetors professionally cleaned and rebuilt with new gaskets, needles, seats, floats, etc.

Now: when I add gas to the fuel tank the petcock flows fuel from ON, RES or PRIME settings. It won't shut off.

As a result, the carburetors overflow. ALSO, I hooked up a single-line remote fuel tank (ON/OFF only tap) and when I leave the tap in the ON position the carbs overflow. It is as if the needles/seats won't shut off. The carbs leak out the overflow tubes on the bottom of the bowls, nowhere else.

What did I miss? Where is my leak coming from?

Many times when a carb is disassembled and cleaned, the needles will stick a bit until everything inside settles into place. Put the bike on the center stand or have someone hold it upright. With the fuel on, try tapping on each of the float bowls with the plastic end of a screw driver. This sometimes vibrates the needles into place. Leaking like this can happen even on clean carbs that have been dry for a while. It may take a good bit of tapping to make the needles drop.

A properly rebuilt petcock will not flow a drop in the ON or RES position without vacuum present at the diaphram. PRIME flows all the time.

A properly rebuilt set of carbs does not leak. No matter how much gas/pressure is present on a gravity fuel line.

Float needle/seats should be set and pressure tested properly prior to the carbs being put in service.

Sorry for your frustration, I would talk to your mechanic.

GL.