Dropped Valve, Piston damage 2000ks?
 

DROPPERD VALVE Hi, I recently purchased a 2006 model XTX with 500ks on the clock. At 2000ks and taking bike up to the rev. limiter,(no rev counter) a valve dropped and did the piston in. Is this common on the yamaha 660cc XTX? Yamaha said they wouldn't cover the repairs even though the bike is only one year from purchase, and in the warranty period, if this was due to over reving. Isn't a rev limiter supposed to stop over reving, with it's electronic cut out?
Mitch

Dont think this is a common problem from what i know of the XT's engine. Very supprised your yamaha dealer will not repair it under warrenty, i think i would have a very harsh word with them about it. But they will probably just refer you to some small print somewhere.

As for the rev counter, they are only there to tell you how hard you are reving the engine, a rev limiter is a different thing all together. My old deauville had a rev counter but no rev limiter but have been told that if you rev it past 10k rpm the crank will break under the pressure and engine will go bang (some london courier did this for the crack supposidley).

Its was maybe something to do with the engine still not being fully run in and possibliby this is the cause of the breakage.

Feel for you about this. :sad1: as said before i would have a read through the contract of the warrenty and have a harsh word with them about it. My yamaha dealer sounds very much like yours and would not even give you a few tank of petrol let allow fix something under warrenty.

Is the bike standard? I wonder if it is modded will they not honour a warranty based on that? I would of thoughts a dropped valve would be covered within the warranty period as its a mechanical failure.

Maybe a more enlighted person will clear this up. I bet that will cost a pretty penny.

Yours would be the first XT660 that I know of to drop a valve.

I would need to see the parts of the valve train to determine what caused the valve damage.

Did the spring break, did the spring seat break, did the valve guide come loose, did the valve snap in half, did the cottors come off or break, what is the condition of the valve end at the cottors.

If the cottors came off & caused the valve damage what is the spring tention as per workshop manual of the valve springs. Weak spings can cause this.

Only knowing all these facts could a dealer say it was warranty or not. Did they strip the motor? Is you bike standard?

If you are after parts PM CaptMoto he has a good second hand head complete, off his first motor.

Yes my friend, as Kev said I have 2 spare engines to sell for parts, anything you need let me know, head / piston / valves / cam, the lot!