Not sure yet. That's why I am asking so many questions like, "Was it the dealer that said shims were needed at 1200 miles" (Which seems rediculous in my opinion and should definitely be covered under warranty). As far as Valves mushrooming, I need all the facts: What Mods were done to the bike? How competent is the person who adjusted the valves? Was the engine run hot repeatedly? There's not really any significant wear going on as far as valves go. Also, The wear generally causes a gradual loosening of the valves which will create a little tapping noise. Some people just shouldn't be working on an engine and I believe that That's 99% of the cause of some of the so called horror stories.

 

I know what you are referring to. I've also heard that from an entirely seperate source from a suspension guy here in NC who raced KLX300's. Apparently it is a real problem, but I suspect it is limited to high revving conditions like racing or riding like you are racing. The guy I spoke with said that once the valves start moving, they go out real fast after that and that the cure for him seemed to be sending the head off to a machinist and replacing the valve seats with brass seats or something like that.

But I doubt its anything you have to worry about unless you are really pushing the engine to its limits for many hours on end.