Im thinking its mechanical not electrical. Could be valves clearances, or the auto compression release isnt working correctly.

In the past week (or so) someone posted the availability of the manual for the FI models. Get that and check the FI schematic. I suspect a sensor is not working as it should.

I too would suspect a faulty sensor. In particular, if the ECT sensor (Engine Coolant Temp) is defective, this could result in this behavior.

Possibly bad connection at the battery or bad ground?? I've had that happen on my truck. Starts great cold, but warm/hot the motor turns over so slow it doesn't even fire. Easy enough to check may be worth a try.

i have problem , i have manual for the carborator version , i need manual for the EFI version , where i can find it?
thank you

Izzy, go to the "Search" tab in the blue toolbar near the top of this page. Type in "KLX manual." Follow the yellow brick road..... ;)

Link here:

https://www.kawasakiforums.com/forum...-manual-37294/

Hey Izzy
Did you sort out the problem? What mods have you done to EFI bike? Airbox lid off?
I had the same starting problems after I modded to 300. Getting too much air and not enough gas on start up from hot. Had to turn my idle screw out to hot start, and do not open throttle,
On cold start the EFI runs a richer mixture and bike runs well. If you have done too many inlet mods you will be running lean and battle with erratic behaviour when the bike is hot.