I have found that Hondas and Suzukis are pretty clean from the factory, but still you want to be on the safe side. Yamahas are terrible. I don't think they flush them at all at the factory.

 

about the cold start my quad dosent run eather right away so what i do is start it full choke and rev it for a bit then shut the choke off and still rev it for a bit then it should idle. Also when i ride a hear that noise to and what i think it is the chain roller because you hear it more when you go off jump and the swing arm is hanging but that just what i think it is

 

You can easily cure the cold bloodedness by installing a larger pilot jet in the carb, they are very lean from the factory on the pilot. Stock size is 38, I switched to a 42 and problem is gone....

 

I think your right russo, thats when i hear it also, when im in the air.