They can make a bit o' noise.
There is noise and noise tho.
My clutch doesn't rattle, it judders like a c*nt on idle. 
Pull it in and it goes away.
I'm sure its a duff bearing or worse ..
Sure, zxr's do 'rattle' a bit but mine is clearly suffering something other than the standard 'personality'.
Also, cam chains shouldn't rattle and neither should top ends. If the clearences are set right and the tensioner is working/cam chain is within spec it should be quiet.
BTW it can also be quiet when the valves are way way to tight 
