Plz I need some advice!!

[jliupakka]

I just bought a 92 Katana 600 and dropped a new motor into it and now for some reason i will be riding it down the road and its almost like once the bike gets hot, it will stall out and then i have to wait for it to cool down before i start it again and then once it gets going it will just die again! All i want to do is just ride. Can anyone help??? (Also its the air cooled motor!!) Could it be the signal generator???
Thanks
Justine