could be the pilot, jet to big or small how hard does it start,
i would start easy and adjust the air screw on the side of the card some where it may have a brass plug over it if so drill a small hole not to deep and thread a srew in it and pull it out with pliers then you can adjust,
every little quad i have worked on has carb tuning issues from the factory,
i work on 4 of my buddies raptor 50 and 80 and every time its the pilot clogged it is so small it dont take much every outing its clogged i tell them to leave the gas on to help but they dont. you may have the same thing try that first. remove the pilot and spray it out make sure you can see day light through it, once again very small hole like a human hair or some thing.