When the bike turns off, sometimes it helps to know what DOES work...to help you zero in on the problem...i.e. if your turn signals and headlamp are still working then it is likely the security system (TSSM) is working OK, so you can concentrate on IGNITION and FUEL issues. If starter and solenoid engage and turn over the engine briskly, but it still does not start...the primary electrical system is likely okay.
Here is where you are at a crossroads in your troubleshooting: 1) Check fuses and controls like the kill switch, 2.) When you shutoff ignition and turn back on, do you hear the EFI "buzz/bump" indicating fuel pump is working, 3) If carbureted, do you hear, smell or see fuel squirt down the throat of the carb when twisting the throttle (my Sporty has an accelerator pump), 4) pull the spark plugs and check for smell of unburnt raw fuel, if none the bike is not getting fuel or obstruction...BUT...5) Confirm your IGNITION (HV secondary) is working by pulling one of the sparkplug boots, sticking a screwdriver into one of them and lay (or tape) near an exposed aluminum fin at the cylinder head, close to the gap 0.035" plug gap (or double matchbook cover or thickness of a dime) and check for crisp blue spark, check the other plug/cylinder as well, but if one is dead the other is dead also otherwise your bike would be running on one cylinder which again would be a helpful clue.
Now from the above tests you should have a pretty good idea what is stealing your "thunder". BTW this is your very basic "Road Side" or Shade tree test procedure; if at home, you have your manual, tools and DMM (Digital Multi-Meter) to speed and hone your troubleshooting craft skills and luxury to go to your nearby HD dealer for help.