Quad not starting

My ex isnt starting.........i havent ridden it or started it scence november because of my broken foot.I am able to ride now and i went out to start it and it wouldnt start soooo i but the battery charger on and it came to life a little more but it didnt start..then i kept trying and all of a sudden BANG! a flame shot out my muffler and little black chips came out too...what could be wrong?

[Wheelie]

There is a little screw on the bottom of the carb, loose it and drain some fuel. Drain about 1pint of fuel out and try starting it again. If it still doesn't start, change the plug.

Good Luck!

[Stevo]

Yeh change the plug. Then if you have a heater and a garage let it sit in there for a couple hours.

Remember to pump the throttle a couple times before starting!

IF you have an aftermarket CDI box,,take it out and put the stocker back in...

Well i got home then it just poped in my mind......after a big bore job and when the carb is tuned to the unbroken in piston it will run perfect BUT my piston is well broke in now...sooo we got the little screwie thing that gose in the top of the carb and turned it 3 clicks from the lean to the rich.and bang the thing fired up like no bodys business so all is well.:p

[TRX250XFIRE]

Hey, i have a friend with a 400ex. he says that he rode it to a friends house and it started great. but then it sat there for a week and that weekend he went to start it up and he got nothing. he says the motor is turning but it just wont fire up. then he though that i might be the type of oil he is running because it was a thick racing kind. u think that that would do it or do u think it could be something else? if the timeing was off on it would that have any effect on how it would start and would something like that happen that fast? i told him i would ask on here because u guys know just about everything so..
Thanks,
Cody