GPX250 1989 won't start when hot

[MotorMan75]

I have a GPX250 89 model which works perfectly fine and runs great. However when the the bike stops after getting hot it will not electronically start it just keeps kicking over without starting. It will clutch start though? Has anybody had this problem before I'm not sure how to fix it. I've cleaned the carbys out 3 times and checked the coils for spark when hot and appears to be sparking ok.

Feedback anyone?