I have a 2005 suzuki s40 boulevard and whenever i pull the choke out the bike will stall. I can start it without the choke but was just curious why the choke kills the bike. I tried the choke i in three positions and nothing seemed to work.
It kills it from lack of Oxygen, that's how a 'CHOKE' works.
As for the cure - Make sure your air filter is clean, a dirty air filter makes a very effective choke. Check the tension on the choke cable, it should be loose when not in use.