Unfortunately, the battery doesn't always die at home and you have to jump it.

 

I'd buy a battery load tester to check to see if the battery has the nads you need to start the bike.

 

My policy is if the donor battery is in a car/truck the ignition is OFF.

Hookup procedure to prevent voltage spikes to the ECM/electronic systems is:

1- pos to dead batt
2- pos to live batt
3- neg to live batt
4- neg to ground [earth] (to prevent spark near the donor battery)

Reverse order for removal.

 

...follow this man's advice..."he knows of what he speaks"...never-never-never jump your HD off a RUNNING car battery...think of it like this..a car battery has to turn over 200-400 cubic inches of car engine on average...why the hell would you have to have the alternator putting extra juice into that battery, just to turn over a 2 cyl, 88-103 inch engine?....don't do it