I have a 1985 Sportster XLH 1000. It will start first time and idle great. Hit it wide open and hang on. The problem is that when you are just trying to cruise at a constant speed it will cough and miss out very bad. Go down the road at a constant speed and it about feels like you are going over the handle bars from it coughing. The bike is all stock except it has pipes and a electronic ignition. I have rebuilt the carb and put new gaskets in it, no difference at all. The carb is a factory Screaming Eagle Kheien. The main jet is .160 and the slow jet is .58. I have put new plug wires and set after set of new plugs and have even got the plugs from Harley and no difference. I have leak tested and even just replaced the intake rubbers and still no difference.