While I never owned that exact bike (but have started and rode them while already warm), normal procedure IMO would be choke on, throttle closed. If that did not work, I would crack the throttle slightly and try again. Something probably is screwed up if it is that hard to start. The tiny pilot jet might be partialy plugged or maybe someone screwed with the jetting or the airscrew at some point in it's life. With my luck lately, without seeing/trying it, my best stab in the dark is a plugged pilot jet due to the crappy formulation of gas in the past year or so. I know you said you cleaned the carb, but unless you visually verified that the tiny pilot jet is actually unplugged, that is my initial gut diagnosis. All that said, it could be anything.
