Nah, it would not affect the temps. But make sure you go with a high-heat paint to be safe, such as that made to use on BBQ Grills. Personally I would spend the extra time and money to take it apart and get the frame powdercoated. It will be a much more durable finish. I have a friend that just spray painted his, and after a couple of years of changing parts and whatnot the paint is worn off in spots and looks horrible.