Hard to start when hot

Is cranking speed slow? Do a voltage drop test on battery cables.and a high output amp meter to test starter draw. normal ampere draw should be 250-350 amps cold and 300-375 amps hot as engine turns these readings should drop to 200-250 amps if not bad starter.

You cannot alter the ignition timing, it is set by the ignition unit and the flywheek key, if it has sheared the key it will knock the timing out, if the valve clearances are not correct the auto deco valve in the engine will not work and will increase the compression to the point where the starter motor cannot crank the egine over.

There is no reason for the idle to take 10-15 seconds to slow to normal. perhaps you have a vacume leak. check all your seal and gaskets between the engine and the carb.also when it is running spray gummout spray or equivilent around the gasket edges between the engine and the carb, if the idle increases when you spray then you have a vacume leak. (intake leak). It may be that this is causing it to be hard to start when it is hot.(not getting enough fuel)

try to adjust the carburetor air adjuster , some klx has blind the adjuster , dont worry you can only pull that put ..

change spark plug plug gets hot want fire

Might be an oil issue. Oil when hot might be too thick for the pump to pump the oil easily in the engine. Check that and if not that come back.

You will have to check the float level of the carburator, try too, to blow out with compressed air the primary jet.
You will also have to reset the air-mixture screw and its better to have it a little on the rich side.
Also check the spark plug gap.
Hope this helps!

I think it may be time to change the spark plugs and wires.

hi there matey,, if she starts perfect wen shez cold ,,and u ride her up the road till shez hot,, does it start misfiring while u are riding it,then a quick check will be needed, if it does misfire then soon as she misfires while riding,,kill the engine and wip out the spark plugs and check wot the colour of the plugs are,, they should be a biscuit brown colour ,,either 1 and 4 plugs or 2 and 3 plugs will be the same ,, if say 1 and 4 are not a brown colour then u need to change that coil to 1 and 4,, at the end of the day mate ,, if she doesnt start wen hot ,,its usually a coil that is the prob,, any more help u need come back,, cheers

It's time to adjust the valves. You have tight valves and most likely need to adjust the cam chain. This is classic when the valves are tight. Most likely you can start it up when cold ok but after a few minutes performance deteriorates this being due the valve lash being to tight.
The miss fire is due to a lean situation.