81 Kz750E2 cam chain tensioner

At the beginning of the summer I came to this site for some help with my kz750 (jetting issue). Well I'm back again.
The bike ran awesome all summer and fired up with the lightest touch of the button even when cold. I ran this bike down the highway for hours on the stock gearing (80mph=~6100rpm) and she still goes great. Only 24k miles.
The problem I'm having now is quite a racket coming from what I believe is the camchain tensioner. When it starts cold, around 30degrees F, it makes a loud clatter under 1300 rpm. If I choke it right it spins 1500 while warming up and sounds normal with just a slight hint of the clatter, once warm though the noise stops completely, even when idling.
I have read from a few google searches that the stock camchain tensioner on this bike is more or less junk and that some people have fitted aftermarket auto and manual units. I'm looking for some advice on what, how and where I should go about fixing my small problem.
The bike still fires on a tiny tap of the starter button, and there is certainly no shortage of power.

I actually found the stock tensioner to be just fine until I stripped a thread. So I bought an Ape type manual tensioner which is excellent. Easy to install. As far as I remember - set the T 1-4 mark on the timing advancer with the fixed mark. Remove the old tensioner. Install the new. Turn the bolt until you get resistance from the cam chain and then back off one flat of the bolt and set the locknut.

Are you sure the racket is the cam chain ? Cam chain noise usually stays as the rpm increases. Primary chain can make quite a racket at low rpm and then go away when the rpm goes up. Mine use to make a good racket at idle. Anything less than about 1100rpm. Or when warming up. A god carb synch can help.

To narrow down the source of the noise you can hold a dowel or long screwdriver to different points on the case and hold the other end or handle up to your ear.... a kind of crude mechanics stethescope.