The name that failure game

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omegas
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#21 Post by omegas »

wrist pin broke

wistech
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#22 Post by wistech »

QUOTE
Originally posted by MX Quad Dad
After what has happened to our Moto I would say cam wore top of at least one bucket (starting with the gear side of the exhaust cam) mushrooming it out and causing the bucket to seize and hold the valve open.

Just woundering if anybody has an ideal what would fail first if there were short segment of no oil supply to the engine? There is a lot of oil slinging around in the crankcase, and there is a lot of pressure required to open the valves.


The direct wear parts will wear first. Camshaft lobes and cyllinder/piston . The crank/rod/cam bearings has roller/ball bearings and will survive with out oil for a while.

wistech
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#23 Post by wistech »

OK times up for best guesses. I suspected a broken valve myself.
I just dropped the oil and the filters are all clean with no metal in the oil. That would tend to indicate a hard part break.
A couple hours and the winners will be anounced.

USAMoto00
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#24 Post by USAMoto00 »

Done yet? lol:deal:

wistech
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And the winners are................

#25 Post by wistech »

Brad77
******
Ironside
:clap:

You 3 were the first to guess correctly

****** hit it on the head. The left exhaust valve broke off at the base and dropped down into the engine.

PM me your addresses and let me know which prizes you would like and I will get them out to you.

I have lots of great info to tell from this motor. Ill post pics of the damage and good news when I get home. And yes there is good news .

USAMoto00
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#26 Post by USAMoto00 »

So only one valve was broke?

Happyboy
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#27 Post by Happyboy »

Usually when a valve breaks it takes out the piston and liner. Wistech, that the case here?

And why does it have to be only the top 3 correct? I was right, just not quick enough huh? sad.gif

wistech
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#28 Post by wistech »

Sorry Happy ,I stated the rules in the first post. Just be glad you were correct and jump on my next quiz.

On to the carnage.
The left rear cam lobe had pretty good wear. The head of the valve broke off the stem ,moved over to the intake side and the piston smashed it through the intake valve. Breaking it into 3 big pieces.

wistech
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#29 Post by wistech »

The head dont look so good

USAMoto00
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#30 Post by USAMoto00 »

3 valves, 3 pieces! C'mon I said that! lol(close enough)

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