My quad is Running like crap help please...?

Alright, I own a 2004 Kawasaki KFX 700 and whenever i start it cold it makes This hiccuping sound while it is running, It sounds like its originating from the carburetor. I replaced the spark plugs but it still does it. It kinda skips a beat every once in a while, its random and it keeps killing itself If i don't give it gas. It doesn't do it while the choke is on at least I don't think, and after I ride it for a while and it warms up it stops... what is goin on?? Timing? bad valves? carburetor??