Just because a few people have gone so long on stock valves doesnt make it smart for someone to go 47 hours without at least checking the vlaves:excuseme: I thought my point was pretty clear.
Like I said above, going that long without checking to see if clearances were in spec is not smart. People make the yami 450 out to be some sort of blue XR, which is not the case.
Well, you got me thinking, you know, and my '06 was out there in the shop with the tank off, anyway, and being that it has about 75 hours on it, and no clearance check since it had about 15, it needed to be checked, by your standards. So I did.
Now that I have checked them, what am I supposed to do with the fact that it doesn't need an adjustment, and the clearance hasn't changed in the last 60 hours? Will I be less likely to drop a valve now that I have done little more than get some fresh air under the cover?
Only one form of neglect can lead to a valve head breaking off, and that is to continue running an engine with one or more valves that has needed more than one adjustment, or that has been shimmed more than .10mm from its original size. Obviously, this does not apply here. If a YZF valve simply breaks at the stem/head joint under any other circumstance, that joint was defective, simple as that.
Your personal campaign against 4-strokes on the basis of how expensive they are to repair is interesting, but adds nothing to the subject of this thread, unless you count "I told you so" as being pertinent to handling the repairs of this gentleman's broken engine. Calling any of us "tards" is not acceptable.