First - DO NOT operate the bike in the condition it is in. I would buy some new intake manifolds as yours are most likely cracked or not sealing and leaking cold air into the combustion chamber. This cold air (especially cylinder #1) is being focused on your piston crown and excessive heat is the result. You WILL hole a piston if you continue without replacing the intake manifold.
Second - Remove your carburetors and disassemble. Soak bodies in STRONG carb cleaner and blow out all passageways with compressed air. Then buy some rebuild kits and rebuild but you will need to buy a few more bits... get four #112.5 main jets and four #17.5 pilot jets and install. Leave the eclip on your jet needles where they are for now. Lightly seat pilot fuel mixture screws and back them out 1.5 turns. If you have a flat spot off idle, move the eclips to number 4 clip position (as measured from top). Also buy o-rings to replace those on the pilot fuel mixture screws (if they don't have them in the kits) and NEW orings for the main jet holder tubes and for the bowl screws.
If you do these things, it will very like fix your carburetion issues. Cheers!
