Puttering Start

[RidrKFX]

i have 03 kfx400 and like a day of sitting in the garage and i go to start it up it take a little while before it while start up and when i go to take off it starts to putter and back fire in bottom gear when i give it some....what do you might think is causeing it to do that?

[RiderTRX400ex]

Jetting:devil:

[FoxProRacing]

you are lean then your motor don't have enough gaz to run good