I have a 1987 Heritage. 1340cc with 11,000 miles on it. My problem is the bike will start but runs really rough. It will idle like that and all of a sudden the engine will run normally, then I can crack the throttle and everything is as it should be, for a minute, Then it begins to run "choppy" again and dies. I have replaced all fuel lines, used new fuel, cleaned and serviced the carb, changed the plugs and wires, changed the coil. Now I am at a loss. I have checked all the wiring and it seems fine. I haven't been able to ride because I can not figure this problem out. Could the ignition be causing it? I have a HI-4 Single Fire Street module. Can anyone help? Also, wondering it it may have something to do with sticking valves?? No engine noise though.