bike is struggling to idle,any solutions?

my bike has been repaired the only problem is it doesn't idle very long, ive fiddled with the idle screw and still not as good results, cleaned the carb and air filter. it will idle for about 13-15 seconds then shut off, i have enough gas so what could it be?

Are you getting a good stream of gas into the carb? Undo the drain plug and turn on the gas (make sure you have a jar or something to catch the gas!)

Air leaks? Have you gone over all your bolts?