TOPIC:

I received an email from Liska Racing (Gordon)  in response to my CCT Roller query.  His site (if you scroll-down enough) shows an OEM roller. 
From Gordon : Correct. That part number is no longer available. I would have to see what that guide looks like.　
I asked how he would fashion one:  "Yes I would press a bearing into it. It would look like the KZ650 roller I sent you a picture of. Metal hub with a plastic outer ring bolted in between".

The OEM Rubber wheel is Bonded to the bearing shell.  "Vulcanized" in a mould. No amount of "egg-smashing" can reproduce this procedure.  This is the hurdle to over-come. 

If this is the case - I can make it...... but first must exhaust options using a J-78 bearing.  
This is from other Kawasaki's

 

This is what Gordon would make

 

This my mock-up using Nylon


 

Just to carry on the discussion for the benefit of the membership-
This is a new tensioning sprocket from Kawasaki purchased 4 years ago

It's a nylon sprocket and it would have a J78 bearing press fitted in to it directly, so I see no reason why a Nylon or Delrin tensioning roller couldn't be made up in a similar manner provided the correct interference was maintained. My only concern would be lateral tracking due to a loose chain if the chain tensioner was a manual tensioner and not spring loaded. So bearing that in mind, I would probably machine a couple of vee shoulders on the outboard edges just to ensure that tracking was accounted for.

This is the KZ1000 tensioning roller I believe.

   

It's a nitrile roller vulcanized on to a steel? bushing. As I remember it, the roller is 46mm in diameter and the bushing is 13mm ID. so if the bushing could be machined out to the od. of the J78 bearing less .002" and a J78 bearing pressed in, then machine down the od. of the nitrile to 35mm, we'd be in the money. I can envision clamping the roller down to a drill press table and drilling/reaming out the bore. It would be delicate but doable. and machining down the roller diameter while locating around the bearing. All doable but definitely time consuming.
2 viable options as I see it.

I settled on this:  The core is my OEM Sprocket

 

Ended up with a suitable rubber wheel, after 3 "prototypes"

 

Used JB Weld Pro epoxy to bond the two.

 

Looks great !! Let the testing begin.

I'm as confident with this roller as I could or would be with any aftermarket product. 
  Liska has the sprocket covered.  It was great of Gordon to offer to make one and am kind of surprised that these aren't in his inventory.   As our bikes age there's going to be a need for  replacement rollers,  which begs the question: What are those requiring a roller going to use?
I guess if your kid whines that you took one of his skate-board wheels you'll be on the hook for a new one.
 

This is an interesting topic.
Scotch, please allay my fears on a couple of points:    
1.  Regarding the use of epoxy adhesive to bond the rubber to the plastic sprocket centre.   I've never had lasting results when using epoxy on rubber or plastic. I was just contemplating the consequences of failure. Presumably, you have confidence. 
2.  Is that new rubber of sufficient hardness, heat and oil resistance ?

Could this roller be used, with adaptation?  It already has a needle roller bearing, so assuming it is a J78 , the roller would just need the profile flattening off. Not sure about the width though.

www.cybike.co.uk/Shop/Products/all-produ...places-oem-12048-001

Lastly, if    Z1300de in Germany have a good stock of the original though expensive part, if it lasts forty years without failure then perhaps it isn't so expensive. However, I appreciate you like to apply your own ingenuity to fixing things!