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Bits of metal found near inlet valve

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nairb:
Hello, I have owned the bike for over 11 years.  Its done at least 5k miles and has had several oil changes.  I decided to do a general service and check all the usual things.  Its been running ok, but it's winter time so never a better time.

I thought to check the valve clearance on all valves, so off with both the covers.  On the LH inlet side, there were some metal bits around the valve stem.
Pic of the lh inlet valve
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and a pic of the bits of metal.  A solid ring of sorts
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I am wondering if the cam chain tensioner has started to break up.  The cam chain is not as tight as I expected.
Is it possible to remove the lower cam tensioner (below the carbs) without taking the head off.

Has anybody else found bits like these.
Ta
Nairb

Skoti:
It can seen from your photos that the tappet cover gasket has been scraped off with something very sharp which may have dislodged particles of alloy into the head.

If the particles are alloy and not metal as you state, then remove them and you're probably good to go, if not then it looks like a winter strip down and inspection is required...


Either way, good luck and Happy New Year.

Skoti

 

nairb:
Well, I have pulled the cam chain tensioner out and expected to see some problem with it.....
For good or bad, it seems to be ok.
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It would be better to find out what's wrong without pulling the engine apart.  It's not been apart before, and I would prefer it to stay that way.

nairb:
I thought I would post an update.... Other cb/cl450 owners might suffer the same issue.
To recap..... The engine was running OK, but the cam chain was making more noise than before.
So I decided it was time to service the thing.  When draining the oil, several lumps of metal dropped out.  Not good.  Then I found bits of metal around the inlet valves.

So it was obvious that the engine needed to be pulled apart to find the problem.

To take the cylinder head off these engines, the cam chain has to be split.  Oh, great.  Anyway, with that done, all was revealed.
The cam chain guide at the rear of the engine had disintegrated and had let the cam chain run slack.
Here is a pic of the item along with what it should look like.
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The part is no longer available.

So if your Double overhead cam 450 starts to sound a bit noisy ........ it might be best to have a look behind the valve covers. 

Bryanj:
I am sure there was a firm making tensioners but not cheap, Ash would know

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