Low RPM chain type rattle

My '80 is using a stock tensioner with a "back-up bolt and nut".  The current project I'm working on came with a ZX-11 tensioner.  The "heavy duty" spring in the ZX10 tensioner was removed and replaced with a "lighter" one.  The "awl" was removed and replaced with a small piece of brass tube.  The piece of tube prevents the "plunger" from merely falling out.  The end cap was drilled and tapped for the back-up bolt and jamb-nut.
In my opinion which is based on some common sense and over 40,000K on the similarity modified OEM in my '80; It's less about the tension(pressure) that the tensioner applies and all about having the minimum chain-slack to prevent chain-skip.  The lighter spring maintains some contact between the Rubber Roller and the chain via the tensioner and equally significant - eases the wear on the Nylon Sprocket if it's still being used.  A back-up bolt is required for obvious reasons.
 

My 79 is doing that now too. It runs an APE cam chain tensioner which I checked and at low rpm rattle is still there. Engine relatively fresh, I bet it has less than 10k mile since complete rebuild.

My CBX got me to thinking. When I did a synchronization of the carburetors, I purposely made them go way out before performing the adjustment. When the synchronization was not good, even the Cbx had rattle noise. And the Cbx much much much smoother than the KZ 1300.

Which got me to wondering, if maybe a bad synchronization puts different pulses into the crankshaft which causes any one of the internal chains to become noisy?
 

That may be something I check on mine as well. My bike has DFI which is 3 sets of 2 barrel throttle bodies. I would assume these would need synced. The bike sat for 3 years in a hay barn before I saved it from the scrap yard. So thing are a bit sticky.

I will let Y'all know my findings I just have not had the time to dig into it yet.

My rattle at idle noise turned out to be loose Sprague starter clutch..

 

Okay I'm back with updates. Sorry it to so long. This project just keeps getting pushed aside. I pulled the airbox and throttle body's off and cleaned them up. After sitting in a hay barn for 3 years it needed it. I pulled the cam chain tensioner out to get a look inside with a endoscope camera. From what I could see it looked good in there. I also put a tensioner in from a zx1100. I previously stated it had one on it already, I was incorrect. I have no clue why I thought it had been swapped.maybe the parts bike I have has it and thats where I got the idea from. Either way. I started the bike and the nose seemed to go away a bit but after a test ride it is back withu an odd galloping rhythm? It's hard to tell. I noticed the oil is at the minimum oil level when sitting on the center stand. I will have to address that when I get back to it again, I just ran out of time. I will check this starter sprag? That was mentioned in a previous reply also. I saw something about cutting the tensioner spring back a couple coils? I just did a direct swap and then plugged the hole where the feed line came from for the original tensioner with a bolt and crush washer.

If anyone has any comments or sugestions on where to go next or maybe I did something incorrectly. I'm all ears. Thank you all for your patience with my slow progress.

I may be waaaay off on left base here but as I remember it, the zx1100 tensioner housing gets mounted to the block without the spring, then the spring inserted, then the rear bolt. As the bolt is inserted, the tensioner starts to take up the slack. Maybe the bolt you used is not the right length? And since the spring is shorter/ stiffer than the kz1300 tensioner spring, you're not getting the proper spring force?

Not aware of any " feed line" to the tensioner on a zx1100 tensioner.

As for shortening the spring - a lot of controversy on that topic and as far as I'm concerned " the jury is still out " on that one.