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Discussion Starter #1 (Edited)
I'm thinking of buying a thunderbird from my local dealer. However although I'm getting a good deal the bike is undergoing work to sort a Valve problem. The head is off and they are repairing it. My question is what would cause a valve to fail? can it be fixed? Would it be ok later on down the road?.What questions apart from the obvious should I be asking the dealer?
The bikes only done 9K so I'm baffled as to how this would happen. Any help would be great

Jock
 

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Very rare incident I think, these engines normally are very reliable over high mileages. One possible cause is a (very rare) cam chain tensioner failure maybe? (The ratchett fails against sudden extreme reversal of cam chain tension from leading to trailing run. Associated with sudden closure of throttle from high revs without brakes - large engine braking reverse torque on the engine against valve train momentum. Chain slips over sprocket teeth & screws valve timing.)

(just a guess - careful inspection of tensioner ratchet teeth - renew if any doubts )
 

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Not sure what is meant by a dropped Valve??

Only thing that comes to mind is someone had a valve out of the engine and dropped it on the floor and it chipped the sealing face? I am sure that is Not what is meant, just very ambiguous terminology in my mind.

If the valves were not checked and one was too tight. They get tight with wear.

That could cause an exhaust valve to burn.

But as Mike says that would be very unusual.

I've never heard of a burnt valve in a Hinckley T3.
 

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Discussion Starter #4
Denny

I'm not sure either but I suppose I should have put failed/broke rather than dropped. Would wear of a over thight valve happen over 9K miles?

I really posted this to get everyone opinion and to see if this is a know fault in the Tbird.

I'm not very mechanical, I can do an oil change and thats about it so any ideas here would be more than what I've got the noo :)

Cheers

jock
 

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A "dropped valve" is when an intake or exhaust valve literally falls into the cylinder.

Usually a broken valve stem, retainers got spit out off it's groove or broken valve spring. Anyone of these examples ,and some more I can't think of will end in the same results. A valve bouncing around inside the cylinder with the piston. AKA Bad thing!

In the case of my bike a valve (not sure which) had it's stem break. When it fell the piston shoved it right back up into the head. Unfortunately it didn't go back where it came from. Instead it took out the remaining three valves, the bridge between the exhaust valves, the entire head for that matter, the cylinder, piston, connecting rod and timing chain.

As for reliability after repair. I've got more miles on the bike now, than it had when it broke. Just make sure that everything damaged was replaced. Also see if it has some kind of warranty on the repair. A competent shop would stand behind their work for a certain amount of time.
 

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Discussion Starter #7
Spoke to the dealer and he said that when they came to do the valves they found that one of them had carbon around it as if it was not sealing right so they are stripping it all down and sorting it. He said it was no big deal and that it should be out the workshop next week. I dealt with the lad before and as dealers go they are ok. Any ideas if this sounds right?
 
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