2008 Honda Shadow Aero that starts with choke on.  When warmed up, cut choke off, engine quits.  Just started this mess.  Only 400 miles on it!  Changed gas out to no avail.  

I'd start with the spark plugs. Using the choke until the engine is warm could easily have resulted in fouled spark plugs. I don't think I've ever used a choke longer than about 30 seconds, even when the engine temperature was below freezing. I don't use it at all if the temperature is above 50f.

regards,
Joe