I don't ride the thing nearly as much as I should. 2000 Sportster 1200 with only 21k miles.
It was on a slow charge and I figured I had better take it out for a ride since it has been parked all summer long. I tried to start the bike, lights came on cranked slow. I upped the charger to engine start mode and it cranked, did not start and then all electrical went dead. no more headlight, odometer, nothing.

There must be a fuse or something to check that may have blown, but I have no idea where to even start. Please point me in the right direction. Can't exactly take it to a shop because that would involve a lot of pushing as the nearest motorcycle shop is something like 6 miles away!

 

Probably time for a new battery. Take the one that is in it and have it load tested at Advance Auto or other parts store that does free battery load tested.

 

Do you mean it was on a 'slow charge', or a battery tender, "all summer long"?

 

slow charge for a day.

 

If it sat discharging all summer, in Arizona heat, it was probably too late for a charge to be helpful. As was mentioned, have the battery checked. Or the main fuse.

 

No Mai .fuse on that one, circuit breaker. Just out of curiosity did you have the charger plugged into the tender cable? If so those cables aren't designed for that amount of current and any power you were getting for lights was probably from the charger and you popped the fuse in the tender cable. Battery is probably dead.