Yes warped head, No biggie. Get a smooth piece of glass and lay some fine sand paper on it then gently rub the surface of your head in a circular motion, going clock wise then counter clock wise. Now lift the head , take note at the Shiny area, and if you see an area that has not been sanded, it will indicate that your head is warped. Continue as needed to make sure all the surface its flat, do not try to press hard to speed up the process, Take your time and sand it until its true.
On reassemble do not tighten just one bolt then go to the next, Snug each one down then just work each one 1/4 turn at a time until you get to the proper torque, you manual should have that. Most causes of a warped head are either from over torqueing or torquing hard on one before another. The other cause would be over heating.
If you notice its NOT the head, then it has to be the surface of the cylinder ( not as likely) however you can remove the studs and do the same thing to the cylinder.
If you remove a lot of metal you will raise the compression, a small amount won't make much difference, but depending on how bad its warped, if that's the case. If you run race gas you won't tell a difference, pump gas it may ping or knock as a result to a higher compression ratio.
I had to do this a few times, the last one I did this to was my sons KX60 , since then he says it runs much better starts much better , and it don't lose a drop of coolant.
Good luck to you, Hope I was able to help
