Engine(?) rattle during stopping

I've sorted out quite a few issues on my KZ550, but one that's been bugging me is that when I come up to a stop, I hear a distinct rattling of some sort coming from somewhere beneath me. It's something in the engine because when I come to a complete stop, it persists for several seconds then fades. I've bought a new cam chain tensioner (A manual APE one) and I'm fairly certain the cam chain tension is correct. The only other things I could think of are primary chain, but most people seem to have that constantly at low RPMs whereas I only have it from 2-1k while coming to a complete stop/idle, and the clutch although it feels normal, no issues engaging/disengaging. Basically, Can someone point me towards what this rattle is, and tell me if it's something I should be concerned about?

Thanks

Is while your still moving, or when your stopped and just revving it? If while moving, hows the chain and sprockets? Counter shaft sprocket on tight?

It's while I'm stopped as well, and it seems to correspond to engine RPM rather than the wheel or chain.

Use a Stethoscope to help pin it down. Listen to the back of the engine near the rear cam chain adjuster. Then up at the top on the center of the valve cover. If the noise is from here the chain is either to lose on the APE tensioner, or other problems.
If not from there try lower down along the starter motor area, under the cover after you remove it. Thats about as close to the primary chain as i think you can get. See if the noise is from there. If so, it may be Carbs out of balance, as this will add to the chain noise. Or while rare you could have an issue with the primary chain. Only way to check it is to remove the oil pan and measure the slack in the chain. Look at the multi link belt for damage and measure the play. If over 25mm/ 1" then it is considered worn. You would have to split the cases to replace it.

Hm, stethoscope might be difficult since the noise is present only very briefly...It does sound like the classic KZ primary chain rattle only not as harsh, and it doesn't seem to be coming from the top end although it's difficult to tell in such a short window. I've read that the primary chain rattle is nothing to worry about....

I don't know if you have the means to make up a video, then post up a link to it on say You-Tube or something? Moving the mike around slowly, as you try to recreate the noise?
Carb sync and chain noise is usually greatest at low Idle. So if cold and running a bit slow and rough the chain would be loudest. If its as you say and above Idle, but not at higher RPM, then it would be good to have a listen.

I don't have my GoPro at the moment but when I have it i'll try mounting it above the engine and go for a ride. It's not actually at high RPM, it is at idle, which is why i was thinking primary chain. It starts essentially just as the bike reaches idle when coming to a stop, goes away if i rev it above 2k, and will generally go away after ten seconds tops.

I suspect a carb sync would help. Ed