APE Tensioner Revision

I've been using the same old APE tensioner since long before cheap knock-offs were considered 2b a legitimate alternative.

Had three problems with it though...

First...the rear cam-chain guide shape distorts similarly to that when using the original automatic tensioner.
I attribute the shape distortion to severe operating pressure with the tensioner rod which end shape differs from the guide recess against which it presses.

Second...to replace the small o-ring between the lock nut and tensioner body, a steel pin has to be removed that is inserted through the end nut and rod.  Only then can the itty bitty leaky o-ring be replaced with a new one.

Third...the adjustment rod was too long for access with fingers and a wrench without removing the carbs.

The solution was one 3/8" x 16 x 3" +/- stainless steel carriage bolt, cut to length, with one lock nut and two nuts jammed together at the end where a flat screwdriver slot was cut for viewing the tension rod position.


 

 



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I don't have the APE, but run a manual tensioner, and always bothered me the hard metal tip of the rod. 

  ....The aftermarket manual tensioner makes maintenance of the top end a breeze.....  as is very easy to loosen or tightening,...and also I can change anything on the carburators bottom w/out removing them from engine....... but that hard metal tip makes the guide distort, instead of the soft tip of the stock tensioner.       Wish they had a soft tip as the stock ones, ,,,,and looking at your picture makes me decide going back to stock.. 

hugo wrote:

I don't have the APE, but run a manual tensioner, and always bothered me the hard metal tip of the rod. 

  ....The aftermarket manual tensioner makes maintenance of the top end a breeze.....  as is very easy to loosen or tightening,...and also I can change anything on the carburators bottom w/out removing them from engine....... but that hard metal tip makes the guide distort, instead of the soft tip of the stock tensioner.       Wish they had a soft tip as the stock ones, ,,,,and looking at your picture makes me decide going back to stock.. 


 

Whatever guide distortion I observed appeared to be minimal after four years of use.  That could be attributable to luck, but I was willing to take my chance on the assembly functioning properly by utilizing my known-good high quality (accurately machined) tensioner body I purchased new, along with a nos high-quality Genuine Kawasaki chain guide to start with.

That nice rounded carriage bolt head seems to fit the curved guide recess nicely, which may help to maintain chain alignment and tension when adjusted correctly.

BTW, the stainless carriage bolt, nuts, and o-ring are all readily available at the local hardware store! 

While this combination of new and used parts seems to function well, this project was attempted only after I considered and accepted that risks exist associated with mechanical failure, which we all must do for the safety of others and ourselves.

I am currently fabricating my own APE copy to go on my '82 Spectre 750 engine. It uses the same style cam chain guide with the pivot where your pushing against the aluminum casting.

I modifed the stock tensioner to be semi manual (still has spring in it)



I find its too big/bulky and its hard to remove #3 carb float bowl so I decided to replace it with the much smaller APE type. I will be using a M10 thread and nut as I hate swapping back n forth between metric and imperial tools.

I plan to make a teflon end cap to push on the chain guide.


 

Here is my DIY fabricated manual cam chain tensioner, about $7 invested in materials.



Its not too pretty as I made some silly mistakes machining it but its usable.
Planning on making several more so they will probably be better.