Motorcycle Repair: Cold start problem, new yamaha lagenda, phillips screw

Question
i have bought a new Yamaha lagenda 110cc, its hardly a week old but i notice white smoke every time i start the bike cold (5 -6 hrs after turn off), smoke lasts for a few seconds only. the first few days the bike would not even start when cold, needed alot of attempts (10 or more kicks), i took it back to the dealer they cleaned the carb, the start problem had gone for a while, but its back again.
What could be the problem?  i dont live in a cold climate area, temps here are usually in 30's celcius.

Answer
When yamaha machines are new they are covered with a  rust protective and a stabalizer is added to the tank and run so that it is in the carb.sounds like that the tank could use a a flush.When you are on the left side of the bike looking at the carb there is a small phillips screw on the bowl of the carb.that is the drain screw,grab a rag and loosen the screw and it will drain the carb...add some fresh fuel and i think that you should be ok.