GYT-R is Yamaha factory performance/race division
Like HRC is to Honda.
Damn ring holders! err pistons.

Anybody have a theory on a cause?
I think a mechanical failure of piston is the only logical culprit. I can't see heat or lubrication (lack) causing anything like that.
Good Luck BRO!

 

did you have the 13:1 piston in there? Ok, I just saw your sig nevermind.

 

Valves are history too. (a shee is sounding better and better)

The tech (just hung up with him) said the failure was piston/rod connection. It (the pin) was jacked against the wall of the cylinder. The circlip is down in the case. Interesting... why/how did that pin come loose with so little wear/time?

All the info is @ Yamaha now and the dealer is expecting a call today.

Funny... the service manager was right there (could hear him in the background) the whole time I was talking to the tech. He kinda pissed me off yesterday and I ended up talking to the owner about the whole thing.

I'm still thinking positively about the outcome.

selector

 

I have a few theories, but need better pics or descriptions of the parts

 

I gots not problem with 'em.

Aside from all that which side let go Exh/int?
?

what was happening when it went?
Just putting down the trail - a minute out of camp.

How load was it?
You mean how hard was I running? Had just come off idle.

Who did your cam mods if done?
YZ cam - Dealer

selector

 

Good luck....

 

The dealer installed your piston too??

 

Everything. I did not take delivery until all (except kickstart) was done. I went back and had the kicker done about 2 weeks after delivery - once they had all the parts together.

selector

 

I do. I don't even own one. You can't lump the masses into one fairly heavily modded YFZ.

The clip came out and the pin slid out enough to cause un even stress and then the failure. Sounds like a mechanic, not a mechanical error to me. jmo. Will the dealer back their work if Yamaha won't? That is the question of the day. Hope so.

 

Hats off to the Dealer if they do(and they should)
As far as lumping the masses...I have a feeling this is just the tip of the iceburg

I hope its isolated...as much damage as Yamaha has done to thier reputation in the past few years...this would really hurt

As much HATE as I harbor for Yamaha...I HATE just as much for any of you guys to get burned as hard as us 01 raptor guys...Hey Selector...keep me posted on what happens please


Jason