When it all goes BANG!

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This is that happens when you OEM cam chain tensioner gives up in 4th gear. 

 

Ouch

AHHHH we can fix it. 

It was nice talking to you today Jeff. Hopefully we can get me squared away.

how many hours on the tensioner? Looks nasty!

How  do you know the tensioner failed first.

 

Its possible the valve broke and caused the tensioner to fail.

I dont think there's any way to know for sure.

I don't know the exact number of hours but not very long. I will definitely replace with an APE manual tensioner.

How  do you know the tensioner failed first.

 

Its possible the valve broke and caused the tensioner to fail.

I dont think there's any way to know for sure.

 

how would having a valve break cause a tensioner to fail ?  If a valve breaks, and the tensioner is working, it just keeps on spinning the the cam sprocket and camshaft.. if a cct fails, stuff starts hitting that should be.

That will buff right out.....

how would having a valve break cause a tensioner to fail ? If a valve breaks, and the tensioner is working, it just keeps on spinning the the cam sprocket and camshaft.. if a cct fails, stuff starts hitting that should be.

I am confused by this... don't get what you mean?

I don't know the exact number of hours but not very long. I will definitely replace with an APE manual tensioner.

Do you run high speed in 4th often and chop the throttle? 

Do you run high speed in 4th often and chop the throttle? 

 

I know I do, both 4th and 5th. 

Gotta replace the CCT once a year or go manual.

That will buff right out.....

Yeah , after a Re shim .

pow right in the kisser

 

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every 4 stroke ive ever had gets a manual tesioner off fleabay

Do you run high speed in 4th often and chop the throttle?

I wouldn't say I do it excessively. In this case, I remembered I had some slower riders behind me so I slowed down to check on them.

how would having a valve break cause a tensioner to fail ?  If a valve breaks, and the tensioner is working, it just keeps on spinning the the cam sprocket and camshaft.. if a cct fails, stuff starts hitting that should be.

 

How would it bend one intake, but not the other not be touched at all? I bet the intake head popped off, then a cycle later the exhaust starts to open, broken valve head smashes into the exhaust valve, destroying the chain/tensioner.

Edited by Lead Head

Valve failure for sure, that sux.

Or whoever assembled the head didn't get the locks in right so they popped out, liberating the valve.

Is that an OEM titanium valve, aftermarket titanium valve or a stainless valve? My bet is the latter...

Edited by Eddie8v

How would it bend one intake, but not the other not be touched at all? I bet the intake head popped off, then a cycle later the exhaust starts to open, broken valve head smashes into the exhaust valve, destroying the chain/tensioner.

looks like the other intake valve made contact with the piston also, can see the outer edges look alittle cleaner or shinier. If there was more pics that showed the top of the piston it would be easier see if there was contact.

looks like the other intake valve made contact with the piston also, can see the outer edges look alittle cleaner or shinier. If there was more pics that showed the top of the piston it would be easier see if there was contact.

Nah, that's too perfectly clean all the way around the valve to be from piston impact...  

Edited by Eddie8v

Nah, that's too perfectly clean all the way around the valve to be from piston impact...  

Right, it does look cleaner around the edges because of V/P contact even though the photo isnt real clear in that area . Its easier to see on the piston top but the same thing happens to the top of the valve where the two parts made contact.

Theres not much carbon build up on the head and valves, can tell it was installed not long ago.

Edited by TDW

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