Is the noise getting worse or just the same as it's always been? Kawasakis often have "noisy" engines, especially in comparison with Hondas, kinda comes with the badge. If the oil and filter are changed regularly it's unlikely to be anything bearing-related, so maybe the camchain tensioner is worth looking at. If you have a go, DON'T just remove the tensioner without taking the cam cover off and cable-tieing the chain onto both camshaft sprockets first - with no tension on the chain it's possible for a camshaft to rotate and jump a tooth under the chain, which could end up giving you an expensive repair bill if it isn't spotted before you run it.
