you can determine if its too lean with a plug check. like that guy up there said, cold air condenses more, more air=less fuel=leaner. leaner=more power (to an extent), however leaner, especially on a two stroke can lead to overheating and meltdowns. a two stroke relies on the fuel/oil mixture to lubricate the cylinder walls/crank and keep it cool at the same time. if your running lean (which can be determined by white deposits on your spark plug) you need to buy larger jets immediately to compensate for the extra air entering your cylinder.