2006 softail,mikuni carb,thunder header,new plugs and coil.It has 11,000 miles.Front cyclinder cuts on and off above 70.The front plug is black,I think it is from running rich due to miss fire.The rear plug looks great.So I ruled out carburator and think it is electrical.Any thoughts?
Thanks
D Mac

 

The front cylinder cuts out above 70 whats?

Yes - it's electrical. I vote a bad coil.

 

Might want to check the plug wires also. You could try switching them front to back and see if the miss goes to the rear cyl. Otherwise, might be the new coil like said above. Did this start after you changed the coil, or was it doing it before?