KLX250s, it's been my observation have always been difficult to start when cold. So I was surprised when the 2019 EFI model I bought second hand, exhibited the same characteristic. It would take up to 3 separate stabs at the starter before it would start and continue to run typically. A minor nuisance. I performed the cam mod, w/o disconnecting the KACR, added an EJK tuner, running the lidless setup, with a Delcovic slip on, nice unit by the way.
So anyway, not sure what happened but that bike starts right up now??? It did seem to idle a bit high so I rolled that back a bit, whatever, bike is running better than it ever has.

 

Never question miracles. Be happy when they occur.