Speedfigh 2 70cc cuts out and dies

Hello i put in a 70cc about a month ago and then about two weeks later it cuts out and it didnt start up but if i did only for a bit. then i down jetted to 78 and it starts up but for a couple miles it kepted back firing then it cleared and started working then i went out on it today and it was going fine for about 2-3 miles and then it died i had to wait about 30 minutes to start it up again its like its over heating but ive got the cover on it so i dont know whys its happening i dont know what to do please help thank you

 

Did you run it in properly?
300 miles at around 30mph?
Whats the current compression test reading?