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Discussion Starter #1
So I decided I should check my valve clearance after about a year and I don't like what I saw. Exhaust valve...
IMG_20190526_071056.jpg
And here's the problem - Intake valve....
IMG_20190526_071409.jpg

The bike had a bad tick when I got it from my buddy who told me the valves needed adjusting. I adjusted them last June - but I didn't check for any damage. Bike has been running fine with minimal noise - bearing in mind these are noisy engines, of course. So what's your input? Catastrophe waiting to happen? Should I be researching part numbers and addressing this immediately? Honestly I shocked to see this...
 

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I can't be of much help, but having metal bits flying around in the engine is never going to end up well.
The two parts that seem to need replacement(6 and 8 from here) are pretty cheap, but I don't know how much time consuming it's to replace them.
I wouldn't start the engine in this state again for sure and would replace the parts ASAP.
 

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Can't see a thing. There are metal bits in there? You will have to take the adjuster bolt all the way out to get a good look with some magnification at its tip and the valve tip. Then post those pics. In the meantime use a magnet to see if the metal bits I can't see are aluminum or steel.
 

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Can't see a thing. There are metal bits in there? You will have to take the adjuster bolt all the way out to get a good look with some magnification at its tip and the valve tip. Then post those pics. In the meantime use a magnet to see if the metal bits I can't see are aluminum or steel.
The valve stem at the 2nd pic is smashed/cracked.
 

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The valve stem at the 2nd pic is smashed/cracked.
Now I see it. Valve stem or retainer ring? A smashed retainer ring would be bad. Metal likely all through the top end. :sad11:
But if the ring is still holding the bits may still be in the valve box. If it did not hold the engine would swallow the valve in a millisecond.
 

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Discussion Starter #6
Thankfully, I did not notice any metal bits while I was in there. Just a busted up valve stem, as YamTW87 noted. Thing is it runs good and makes very little noise. Bike only has about 5K on it for being so old.
 

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If time is not a problem, I would suggest the following:
1.Remove head and clean it(with gasoline),in case metal bits are stuck somewhere, check piston-cylinder for wear(from potential metal bit) while its off.
2.Replace valve stem+retainer and head gasket and re-install top end.
3.Check and adjust valve clearances.
It will cost you around 35 dollars and a couple of hours depending on your familiarity with this task.

Part numbers:
Valve stem: 5H0-12119-00-00
Retainer: 4G0-12118-00-00
Head gasket: 1NU-11181-00-00
 

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You need a new intake valve for sure. The exhaust valve tip looks like it may be worn too, as it looks like it may be concave. Remove the adjusting bolt and check it.

Get some new valves, lap them in place, and install them. Not a hard job but a little scary if never done before.

Admiral made a valve spring tool from a large C-clamp. If you search the forum you might find a picture of it.

You might have to file the old valve tip to get it to fit through the valve guide to remove the valve. Good luck.
 

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Discussion Starter #16
Thank you for your encouraging comments, friends! I've done complete rebuilds on Briggs and Tecumseh engines when I was a lad - so I'm not terrified of doing the valves on the TW. I just wish I had noticed this over the winter and not when riding season is just starting up here.
 

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Hmm. My eyes are poor, but kinda looks like retainer failure. I’d try the “rope trick” before getting too depressed.
Remove spark plug thinking about timing, fill cylinder with nylon rope.
Rotate until piston pushes against intake valve, secure from any further rotation.
Secure location from any bits getting into crankcase.
Remove adjuster
Compress valve spring and remove retainer bits, and spring.
Clean and inspect.
Reassemble with previously sourced retainers.
This has worked for me. Sometimes the retainers will shatter but still hold things together.......
Not always...........worth a try.
Tonto
 

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Que bueno, but what technique do you use to then compress the valve spring while fishing out the valve keepers? Be nice to know since it allows inspection, clean-out, and a lot of replacement if necessary w/o removing head.
 

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I can't help but wonder how this happened if it was adjusted and torqued to spec.....wrong engine cycle or not true top dead center? Or misreading of the gap due to distorted shapes of the tappet and/or valve stem? Vibration from running high RPMs?
 

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Discussion Starter #20
That's what I have been wondering as well, Trail Woman! I bought all the necessary tools to do the job right, watched the TDubskid video several times, ensured top dead center... I'm rather sure that, as you mentioned, I misread the gap due to damage that went unnoticed. Thanks for hope of good news, arbolmano! But I am being faced with a tough decision now. I'm working two jobs right now and can't possibly conceive of when I'm going to do this work myself. So I hate to admit it but I'm considering the "local highly recommended shop." (I know) My main concern is not with doing the work myself, but that fact that my engine could be opened up for a LONG TIME and I don't want any possible contaminants to make things worse for me later.
 
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