KX 500 Engine in Ninja 500

[Foxx4Beaver]

It doesn't seem to be leaking anymore.

Did you change out the head gasket?

[taddpole77]

I did.  Went with cometic this time.  I had them plane the head and cylinder again.

[Foxx4Beaver]

Excellent!..there's several of us on here using Cometic...you should be all set.

When I do top end replacements/re-ring, I don't take the head off. It requires a bit more of a steady hand when droppin the  cylinder back on, but it's easier than lappin the head/cylinder everytime.

[sandblaster]

Excellent!..there's several of us on here using Cometic...you should be all set.

When I do top end replacements/re-ring, I don't take the head off. It requires a bit more of a steady hand when droppin the  cylinder back on, but it's easier than lappin the head/cylinder everytime.

I've been lazy a time or two myself 

[Foxx4Beaver]

I've been lazy a time or two myself 

Hahaaa 
I like to think of it as "being wiser with age" 

[streetsleeper]

I did.  Went with cometic this time.  I had them plane the head and cylinder again.

I guess you've tried everything. It certainly sounds like it. I'm no expert and haven't even had my head and barrel off my KX yet (I think I know what to expect when I do). But as a mechanic I remember working on all sorts of vehicles and one thing that could cause this is the locating dowels being either slightly off, or sometimes dirt gets beneath them, or they aren't inserted well so that they don't recess to their full extent and are then raised just enough to prevent the two halves (barrel and head) from mating properly.

Really sorry if you've gone through this before, because it sounds like you've been really thorough, but sometimes it's the little things that get overlooked. Best of luck.