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Discussion Starter #1
Hi there,

Getting a little scared now, the top end suddenly started tapping yesterday, I thought it was possibly exhaust gaskets blowing, as I have had that before on this bike from just not tightening up the manifold bolts enough, but I've just replaced them, and the tapping is still there. The tapping did not arrive gradually, over days, it was not there when I started my journey, and was there when I came off the motorway 30 miles later. As for power loss, it is bogging down a little though at high speed, I had put that down to a dirty air filter as I have not changed it for about 12 000 miles, however I am now looking at this as a symptom.

It does sound like a loose tappet, however, as these bikes don't have tappets, I am now fearing the worst, and think that the camshafts are gone. Can I have some feedback here as to what other considerations might be before I feel the need to start a stripdown, and also whether it is worth doing on an old fireblade. I have looked at the following so far:

Exhaust gaskets replaced, Exhaust is only a year old and is stainless steel, looks ok.

Cam chain tensioner is manual type and has been mildly adjusted, though I don't think the noise is coming from there, because adjusting the camchain does not alter the noise at all, so suspecting that and the tensioner guides are ok (However some clarification would be appreciated)

My suspicions are as follows:
Possibly camshaft just broke through it's case hardening and has failed.
Valve seats burnt as the bike has done70,000 miles the last 38,000 by me and i have (probably quite irresponsibly) never had the valve clearances checked.

Please comment, reprimand, give hope.

Regards
Rob
 

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Possible cam towers like you said. Loss of power says the valves do not lift enough, stay open long enough, have more gap to tap.
Smell the oil for burnt aluminum... it's no longer light 'sweet' crude, but metallic in taste/smell.
 

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Discussion Starter #3
Found it, when you push down on the right hand most plug cap the noise stops. It was gas leak after all, now whether it is a loose spark plug or blown out the threads is another matter, but at least we're in the right ball park now. Whew
 
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