I'm needing a replacement head for an 06 engine and I've found a couple of cylinder heads off a 2004 - 2006 KLX300. I think they should fix my 250 engine. Does anyone know of any differences other than bore size between the 300 and 250? The heads look in decent shape at least a lot better than my old oil starved one.

 

Will bolt up fine. I believe the only difference is the 300 has no air injection.

I would replace the valves. Some early 300's seem to have soft valves that move fairly quick.