Looking for advice

I have a KXF 250 2007 model,
the bike will fire up from cold no problem, once warm and choke is off when you rev it and let off it back fires pops and there’s normally a flame out of exhaust, the bike will ride for around 3/5 minutes then it dies out and will not kick back up. If you leave the bike 5 minutes it will then fire up no problem and you will get another minute out of it before it dies again, again leave it 5 minutess and it will fire back up no problem for another minute and so on....

it had recently had a top end rebuild a week before I bought the bike,

took the bike to the the shop last week with the symptoms and it had the following work done

valve clearances checked and adjusted
(all 4 out of spec)

repair cam sprocket
(cam sprocket out of line)

carb strip and rebuild
(various parts missing from carb)

orings and seals

picked the bike up yesterday went out on it today still same problem.... I’m pulling my hair out, any advice would be greatly appreciated

cheers dean

photos below of the rebuild carried out

 

Did you find the problem ? Im having the very same problem with my 05 kx250f , like you i have checked everything from valves to new stator , pickup coil, cdi , plug and even kill switch . Pulling hair out next !