I wonder whether this is similar to the problem I experienced with my factory-new JH600: During those first days of riding the new motorcycle around Chongqing, occasionally, after an hour or so of riding, when I would take a short break to take photos or buy something from a road-side stall, after sitting for a few minutes, the motor just wouldn't catch, even after 10-15 seconds, just turn and turn and turn, even though everything was obviously still warm. I'd have to retry multiple times and turn the key to completely off and on repeatedly and this was cause for some momentary concern.

Will try learn to listen for the fuel-pump spinning up sound, if there's any way it helps in the investigation to look at the wiring etc. of the JH600-A version - the motorcycle is in Shanghai now.