250x braking up

[Honda TRX250ex]

i just rebuild my 250x i put piston rings rockers cam and intake valves in it. but when i went to start it up it broke up very bad
i tryed adjusting the carb to home specs and the timeing is right
me and my dad think that the float bowl is is over flowing and not enough air is mixing with the gas and a tube that comes off the carb is leaking gas
could that be the problem or could it be something else

[2muchquad]

it sounds like you already answered your own question,an overly rich condition will have symptoms like your describing.:)

[Honda TRX250ex]

i set the carb to be more lean but it still does it

[250rider]

mess around with the air/fuel ratio screw

[ZeroLogic]

something was worng with the carb cause we put my 300ex carb on and it ran fine but a ltitle brakng up much better