Today I have been investigating a strange noise my bike has developed. It's a rattle but accompanied by an idle noise I can best describe as a bit like an alcohol racer (not in a good way!). The noise disappears at speed, but it's hard to tell if it's just drowned out by wind/road noise.

So my two initial thoughts were either the unlikely scenario that the cam chain had somehow jumped on one of the sprockets or the cam chain tensioner needed replacing (though I'm not sure this would explain the second noise).

So lifted the valve cover and both cams and bottom crank are aligned correctly.

I removed the cam chain tensioner and on inspection it appears to do what it's supposed to - i.e. apply a constant pressure without retracting.

So my questions are - is it obvious when a cam chain tensioner has gone? and can anyone suggest what else the problem might be?

The bike is on 41,000 miles.

 

Cam chain tensioner id say.
Remove the M6 cap Try slowly winding a long M6 bolt in the back of it using your fingers with the engine running only thread in until the noise stops. If the bolt becomes stiff you've gone to far.
If this cures the noise I'd go and order an APE manual cam chain tensioner.
Or use a washer and nut to lockup the long bolt as below (ok as a temp fix)

 

Ok, so now I've worked out how the automatic cam chain tensioner works I tried manually tightening whilst the engine was running, this didn't make any difference.

Here is a video of the noise which I'd call a rorty rattle:

http://www.flickr.com/photos/8156415@N04/4493756426/

Any more ideas on the cause?

The idle has always been rough so I'm not worried about that.

 

Sounds like my bike when I forgot to tighten the headers after some work, try that and see what it does.

 

I thought you might be on to something there as I replaced the head gasket about 2 years ago. Just checked and the header nuts are tight though.

 

It might be the rough idle causing it to rattle.Could be worth a balance it worked on my mates GPZ turbo.
Is that the standard exhaust?

 

It's always had a rough idle, I've had it since 14,000 miles. It is the original exhaust, I randomly bumped into a previous owner who said he'd fitted an aftermarket end can, I'm not sure if he got it jetted to suit.

I've had the bike since 14,000 miles and it's always had a rough idle. The rorty rattle noise is new.

Does it sound exhaust related?

 

idk if you took what I said the right way, cause the header and head are two completely different things, and when I said header you went on about changing your head gasket.

 

I assumed you meant the nuts that hold the exhaust downpipes onto the head?

I mentioned the head gasket change as this required the exhaust to be removed from the head and therefore it's possible that they may have worked loose after reassembly.

If I've got it wrong let me know.

 

Can you do the video again with a rag over the exhaust to kill off the exhaust noise.