Yep check the needles what size motor did the carbs come from.is there oil in the dash pots or have you got the wrong oil in them(too thick).my engine is a 1330 with a re13cam/11.5-1cr/ported head/free flow exhaust nothing too crazy .I had a 45 dellorto carb on it but sold it and fitted a single HIF 44 carb to engine from 1275 mg metro.That carb worked perfect on the metro but when i fitted to my engine it would only idle as soon as i opened the throttle the engine would die so after doing some home work and about 5 diffrent needles i finally got it right but that shows how important needles are. Give me your engine spec and work done to it and needle codes and what size carbs you have and i be may able to help.Are you using a electric pump or the standard pump is that pumping enough fuel to both carbs check all the basics
