Ye i hear ya, i know that's why the other guys were mentioning your jetting since it only happens when cold... reason i commented on this was when i first got my blaster, it was the summer, and it ran as good as i thought it should, and when winter came, i had already discovered this site and had started to try and plug chop... the plugs were coming out too lean even with increasing the jets, so I put together a leak tester and found they're was a leak at my reed valve... unfortunately, I had been riding with a leak for too long, and within a few weeks of discovering and attempting to fix it with the wrong kind of gasket material, it overheated and the rings smashed together, did some nice damage to the cylinder... so i got to rebuild the top endI:I anyways, my point is my blaster ran ok in normal temps(like yours), but if it dropped to below freezing, it would run sooooo lean there was no top end power, like it was starving for gas... at this point it can only be one of two things... your carb is the issue, or you have a lean condition caused by an airleak or improper jetting... don't be too bummed because at least you have it narrowed down to those things... plus you'll be stoked once you figure it out, don't give up! have you thought about a carb kit or are you pretty comfortable with how clean you got it... sometimes just spraying it out won't do the trick, gotta completely dissassemble it...
EDIT: Also, when you say it starts on the first kick, then won't take gas, do you mean it dies, or it just has no power? When you first start you engine and its cold, the seals are tighter, but once it warms up, any weak areas will open up and allow air in. Someone correct me if i'm wrong about any of this