I usually start my bike with the choke on full but unlike the rest of you I give her some gas while cranking. About 1/3 throttle. If warm out I turn choke off immediately and if cold only turn it half way down for a minute.
My bike does not sound anything like yours. Crank, pause, crank, pause. I also think that is a symptom of too much advance but never sure of this until I check the timing. Do you have an electronic ignition? I guess you do since it is an '82 bike. Be very careful to not crank the engine unless the plug wires are hooked up to installed plugs or the plugs are well grounded. These electronic ignitions fry parts if the coils fire into a blank hole.
You have a good battery and the starter motor is cranking good. It's not either of those.