i have a 81 cb 650 custom honda its a little hard to start untill it warms up and when you get to 3 to 4,000 rpm it starts cutting out and back firing like it running out of gas and i cleaned the carbs. about 15 times am i missing somthing! after it starts it idles fine it only cuts out while driving and a little when you riv it up when you first start it up.