engine not start after the engine was working (hot engine)
 

I own a motorcycle KLX250S EFI 2009.
After that I was start the engine and drive a some distance, as soon as I turn the engine off I can not start the engine again.
What could be the problem?

Izzy, welcome to the forums. We need more information. I'm assuming you turn off the engine, do whatever short task you do, get back on the bike and turn the key to start the engine again, in the span of 5-10 minutes? What happens? Does the engine turn over but not start? Turn the key and nothing happens? Sidestand down or up? Clutch lever in or out? Tell us more.
Welcome again. Plenty of KLX'ers on here to help you!

Even after five minutes I turned the key and the engine would not start, engine turns but can not start.
Clutch lever is not pressed, but also when the clutch lever in pressed the engine not start , i mean that the engine is turns but can not start.
but when the engine is cold , the engine start very fast , sidestand is up.
If I want to start the engine when the engine is hot
I just push the bike and the engine will start.

thank you

Sorry to bother, but it is very important. I have to go to work every day.

sounds like a problem with the bikes electrical system. or the comp that controls the bikes electrics.

So why when the engine is cold the engine start very fast with no problem, but when the engine is hot i have a problem to start the engine?

Find a thread where it talks about drilling out the starter jet to .18". This is a must for some bikes. Also technique comes into play here. When my bike was stock and warm I still needed to choke it sometimes, there is a sweet sopt about half way out on the choke where the bike starts better than if you pull it all the way out and I also had to flog the throttle some.

I have efi model, injected

I dont have a choke.

What does your spark plug tell you? (color/deposit)
After you turn off the engine, wait a few minutes, then try to restart. Give it a good 30 seconds of 5-second starter bursts. Pull your plug. Is the plug dry or is it wet, and what color deposit?
(Edit: Speaking generally, ALWAYS start trouble-shooting with the fundamentals, which may lead you to specifics, like electrical, mechanical, etc., unless it's obvious where the problem is. Experience has taught me.) :)