Was just reading another thread where someone had a similar issue... mine is slightly different. I know I have a short somewhere which is cause the main breaker to trip. This happens without the ignition even being turned on.
Can anyone tell me the most likely culprit here? I don't really know much about electrical issues so I'm at a loss. What could be causing a short if the ignition isn't on?

 

If you look at the wiring schematic in your owner's manual, you'll see where the positive cable goes after it leaves the main CB.

 

On the main breaker output side (silver colored stud on the breaker) there are two wires, a red wire that goes to the ignition switch, a black wire that goes to the voltage regulator, remove one wire at a time and see if the problem stops.

Let us know what you find.

 

The switches themselves have known to go bad. Remove the dash and unplug the switch and see if it still happens if not most likely you got a bad switch... I had mine going bad on the road luckily enough I was across the street from a auto dealership and was able to get some wire and Terminals and jump it out.

 

Take the dash off and have a look at the ignition switch. A shorted ignition switch is a common problem on Evo Softails