Motorcycle Repair: fuel system, petcock, gas cap

Question
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Followup To
Question -
I have a S&S g carburator on a 78 sportster HD. I am having a problem with the fuel flow problem, which is when the bike is cool the fuel filter is full but after a short period and the gas is used in the carb and line no more fuel will flow. The gas tank has been cleaned, the petcock checked and blown out. the lines blown out, the carb examined for the float the works freely. When we take the bowl and manual operate it,it seems to work fine, We moved all lines away from heated parts to avoid vapor locking. What else could it be?
Answer -
Sounds like the fuel filter is plugged. Go ahead and remove it and run a new fuel line to the carb. Try running it like that and you should be ok.
Good luck and happy riding
Mike

I have replaced the fuel filter already and the problem still exist

Answer
There can be only two other things it can be. The valve in the petcock is not opening when you turn it on or the vent in the gas cap is not working or plugged. Try running the bike without the gas cap and see if that doenst solve the problem.
Good luck and happy riding
Mike