Can you jump start 2002 Harley Davidson deuce from a car?

You can do it if there is some power left in the bike's battery. You do not need enough power to turn the starter but there must be enough to excite the fields of the alternator and to power the fuel pump if it is an injected bike. Let me forewarn you though that jump starting a bike by towing the bike and rider with a car is very dangerous. The biker would be far better off being pushed by others or coasting down hill to jump start the bike.

Jump starting any bike using a car can destroy the stator and regulator.