Got my bike fired up for the first time today. Runs great, but the little screw on the left side of the carb (the one with the spring) vibrated out and is gone forever. It still runs good, but I know it serves a function and should be replaced. This is the idle adjuster, right? Does anyone know the screw size and thread size that fits so I can just hop on into the hardware store and go straight for what I need? Thanks!