I was wondering if somebody could help me? I will try to keep this as brief as possible for everyones sake. I own a 2002 Honda CBR600F which has a noticeable rattle between 3,000 and 5,000rpm. I have only noticed it since I changed my helmet from a Shoei to a Index helmet. I am guessing it has always been there, well for the time I own it anyway. It sounds a bit like a loose washer rattle around, so I removed all the fairing and took it for a ride, to no avail, the rattle is still there. It sounds like it is coming from right hand side of the engine.

I did some digging around to the camchain tensioner as CBR's are apparently prone to this problem. I bought a new genuine Honda tensioner from an online part seller, fitted this by the book, but the rattle is still there. You can't hear it on tick over, or if you rev the nuts off it on the sidestand. You only hear it while you're riding and the engine is under load. Shut the throttle and it goes, wind it on gently and its back. Please help me. Is this something I need to worry about or should I just wear earplugs?

Hi Marcel, it's a good thing you're not ignoring the rattle because first off there shouldn't be a rattle. You're right to point the finger at the cam chain tensioner as the most likely culprit. As you said, you couldn't hear the rattle until you changed your helmet and it could well have been there much longer. We're almost certain you've worn the actual cam chain and sprockets to the point where even the new tensioner won't cure the rattle. The bad news is you'll need to replace the cam chain and sprocket, as well as possibly buying another cam chain tensioner, depending on how many kilometers you've put through it with the bad cam chain and sprockets.

A bad sprocket and tensioner can damage your engine big time but one that can be easily fixed. If you going to do it by yourself you're looking at about three and a half hours work.

Whatever you do, don't just buy ear plugs, get the work done or do it yourself before you have a serious engine failure.