Most likely, the choke is not opening when warm.

To check this take the flame arrestor off. Put your hand shift control into throttle only that you use for cold start ups and give the throttle one push forward and then back to neutral. This will allow the choke to close.

turn key to on position (not start, ON). Check for 12 volts at the purple wire at the connector to the choke. ( purple wire is +12 volts and black wire is ground) check between the purple and black to make sure the black is grounded.

If you have 12 volts across the 2 leads the wait a few minutes and then look at the choke butterfly and make sure it opened. The choke is controlled by a spiral bimetal spring that when the voltage is applied it acts like a resistor and heats up and when it heats up it moves causing the choke butterfly to open.

If it does not do this than your electric choke is bad. Replace it if you can.