Main Motorcycle: 2009 Bonneville SE
Join Date: Jun 2009
Location: Asturias, Spain
Other Motorcycle: Yamaha XV1100
Extra Motorcycle: Qingqi QM200GY-BA
Assuming you're using the same starting procedure as when it started fine, stuff like a closed throttle, a little "choke" when partly warm (as per owners manual), etc, the main suspect could be the old pick-up coil or CPS (crank position sensor).
These tend to give trouble when hot and detection is not easy, as it involves measuring its resistance and Sod's Law says that by the time you find the cunningly hidden connector, got your multimeter out, etc the thing has cooled down and measures correctly.
It ought to flag up a fault code and light the engine check light, but it often doesn't.
The ignition coil on EFI models is very durable and reliable and seldom gives trouble, by the way. I say this because a replacement costs £113 so changing it is not a decision to be taken lightly.
Last edited by Forchetto; 10-19-2019 at 09:19 AM.