yz250

I have a 03 yz250 that has a hesitation on hard excelaration , it has a no. 50 pilot jet I tryed a 52 and even moved the needle all the way up and it will still hesitate.So I'm not sure if I need to go up a size on the pilot your if there mite be something else I'm missing.The reeds are v force and are all good it has a FMF gnarly pipe and a eline stator and these came on the bike so I dont know how it ran befor they were put on.Thanks for any idears!