PROBLEM: OVERHEATED COIL, MISFIRE REAR CYLINDER
ENGINE:2007 long block ULTIMA 100ci
SINGLE FIRE COIL, 2.4ohm, 45000volt
IGNITION MODULE - COMPU-FIRE #21835

coil get overheated very quick after short trip.
this is my own build, i started ride my chopper maybe one month ago, last time i get back to my workshop on front cylinder only ;(
is this because i didn't change the advance curve from the initial one (A.C. position 8, RPM position 1 in 50%) and ride bit to hard on the motorway?
please help...

thanks in advance