www.zxrworld.co.uk

When i place my hand over the end of the exhaust and so the noise drops to nothing the top of the engine sounds really clicky/tappatty. Other than the tappeets need doing what else could it be, The noise is generally from the top end towards the rear of the cylinders

zxr's have noisy top ends, just a part of the bike unfortunately.

They are a bit noisey, but not excessive. how many miles has it done on that cam chain/tensioner? have you noticed a change in the level of noise?

pull yr clutch in, and if its really noisy still, id get them done...check the tensioner, they are known to fail

Its done 36k miles so quite high, its noisy / rattley all the time weather clutch in or out.

if its a slightly irregular clicky noise its camchain/tensioner, if very regular its a worn tappett, neither is much hassle to do with the engine dropped, tappets slide out of the way so cams dont even need to come out, and the camchain can (despite the manuals) be changed without splitting the cases.

IIRC yours is/will be a track bike, so set the valve clearances at the loose end of the accepted range, or the valves stretch/expand so much under race conditions that the clearances close up.