Hallo NR's young 'n' old, A good friend of mine has a CBR600 F4i, and for a couple of weeks the chain's had some slack in it. How much? Enough to hear some noises and to see it hanging a little low. I commented today, "Your chain sounds and looks a little loose, mate." My friend replied, "Yeah, bike's due for service. I'll let them take care of it." I suggested, "Why don't we just adjust the tension now, anyway?" And this is what we found... Chain links had a 'clean & worn section' on the inside of the links Apparently the noise is worse under deceleration, which would make sense as that slackens the top of the chain Bad things have happened to the swingarm So how's your chain?! Would be a shame if it was putting nasty scratches in a pretty critical component of your bike, just like my mate's F4i. I think we've caught it in time. They aren't the most popular stunt bike for no reason: they got tough bits. But still, it sucks to damage your baby through nothing but negligence. 1) Loosen rear axle. 2) 'Unscrew' axle/chain tension bolts on each side by the same number of turns until the slack is what is recommended in your manual (on the F4i it's 30mm). 3) Retighten axle. You've saved your bike from damage via negligence.