[The CyberPoet]

Looks familiar, had a valve snap in my Ducati.

Timing belt break/skip?
Or was it too lean in the jetting?

Cheers,
=-= The CyberPoet

[arsenic]

wow, that's bad, I don't know if that piston is cracked, I'll post pictures if it is.

[Visker]

Its what happens when the guy you buy it from does his own valve job.[/quote]

[tzortn]

My Diagnosis:
Fairly low mileage engine.
#4 Carb blocked/lean, tied to aftermarket header and/or K&N air filter sans appropriate compensating jetting at the carb. Cylinder ran extremely lean, overheated exhaust valve and piston face repeatedly, pitting piston face repeatedly and thermally stressing the valves. Exhaust valve cracked, but operator continued riding like usual. Exhaust valve finally gave while opening and shattered valve parts went into the cylinder. Engine turned about another 12-20 times before it seized all-together.
Odds that the rider happened to do a wheelie within the last ten miles before engine failure based on the seized valve: about 35%.

My real question is about the spark plug -- what's left?

Cheers,
=-= The CyberPoet

No way.

That engine turned over 14-27 time before it seized. The odds of a wheelie in the last ten miles a no more then 31.23% I would also add the the ambient temperature was 52.75-66.83 degrees F. With a relative humidity of 49-58.47%. Oh yeah and the bike was painted silver and safety green.

[The CyberPoet]

No way.

That engine turned over 14-27 time before it seized. The odds of a wheelie in the last ten miles a no more then 31.23% I would also add the the ambient temperature was 52.75-66.83 degrees F. With a relative humidity of 49-58.47%. Oh yeah and the bike was painted silver and safety green.

Cheers,
=-= The CyberPoet

[steves]

Interesting. When Kristin's brother blew up the motor in her kat, he sait he was 'doing about 130.'

Piston: http://i99.photobucket.com/albums/l2.../engine002.jpg

Combustion chamber: http://i99.photobucket.com/albums/l2...s003Medium.jpg

[tzortn]

I wonder if the piston burned up or if it experienced mechanical failure. I have seen a piston crown separate from the skirt in a race engine. The crown ended up in chunks in the oil pan. The skirt and the wrist pin just kept moving with the con rod. It scored the heck out of the cylinder wall but the motor kept running.

Usually when a cylinder runs lean you see a hole burned in the piston (like in Steves pictures). That would drop cylinder pressure and reduce the amount of catastrophic damage.

[bswasey]

Ouch, but on the good side, scrap aluminum is pulling about $3-$4 a pound.

[Black_peter]

Didn't another member have an engine that looked like that??

Hmm.. I remember one..

[steves]

Didn't another member have an engine that looked like that??

Hmm.. I remember one..

Somebody had a "running" bike that he thought was dropping a cylinder...

[arsenic]

yeah, I remember that, his engine looked very similar to that.

[badroc13]

Re: if your piston looks like this, that's BAD

Okay, I'm a Suzuki tech, so I've seen a lot of stuff, but I've never seen an engine blow this bad.

That's the piston on cylinder #4, it's totally gone.

Here's what the combustion chamber on the head looks like. I don't know if you can see it in the picture, but one of the valves is completely broken, and one is pushed way up in there. Wow, this motor is BAD.

Why are the pictures dated for 2003?

[arsenic]

I've never messed with the date stamp on my camera, it's on whatever it was on when I bought it. I'll mess with that tonight.

[bubba]

I've never messed with the date stamp on my camera, it's on whatever it was on when I bought it. I'll mess with that tonight.

Don't believe him, its a scam!