in my humble opinion, it sounds to me like it could be a couple of things. first get dummy spark plug and check for good blue spark. then check timing. if you dont have a timing lite, bring up #1 cylinder and check where rotor is. it should be slightly before where number 1 plug wire is located. if all that is good? check vacumm leak by closing both chokes if so equipt. if not, turn idle up on both carbs until it runs. turn them down until it wants to quit. take rag and cover top of each carb slightly at a time. if idle goes up? you are running too lean. another way, spray carb cleaner around base of both carbs, spray intake gasket area. spray small bursts down thru carbs. ill bet you got a problem with ignition system somewhere. did you put dual carb systemon yourself? did it always do this? did it ever idle fine? if the answer is yes to all those? you need to backtrack
