Easily convert auto cam chain tensioner to manual

The automatic cam chain tensioner on my 1979 KZ1000ST failed a few months ago (bearing wear, shaft wear), and I wanted to convert to manual but didn't want to put a new-looking part on. So I converted the original one to manual All I did was cut off the tip of the housing and thread the internal hole for a slightly larger bolt. I inserted a short spacer shaft between the bolt, when threaded in, and the back end of the tensioner shaft to get the tension in the ballpark, sealed her up, and used the bolt to set the tension precisely. It's been working like a charm!

Well done, this will look good when on the motor. I have a 79 650, and I am suspicious of the tensioner failing. I have a rattling in the motor that is intermittent with various rpms. Did yours have any symptoms like that before you changed to the manual set up ?

There was a recall on the early ones. The stock Z1 was manual but was limited in adjustment. I have a APE manual now. Be careful how you adjust it. It can be too tight and cause premature wear even breakage of the chain.
Steve

Yes, I had intermittent rattling as well! It would come and go every few seconds, and happened most at lower RPM, especially idle. I reset the auto tensioner a few times, but it immediately let loose again. I considered getting new parts, but I had wanted to go manual anyway, and this solution cost me only a couple dollars and was easy to do and very secure.

As noted by the other reply here, you want to take care to adjust the tension so that you no longer hear the rattle but no further than that, as with any manual tensioner.

You might also want a lock nut, but I haven't needed one. I did put a little Loctite in the threads. When you put the converted tensioner on, you may note that you need more throw than the new nut gives you. If so, just add a short piece of rod between the bolt end and tensioner shaft end. You want a range of adjustment that includes too loose (the rattle) and just right (no rattle).

Anyway, thanks for commenting!

Thanks for pointing this out Steve -- you definitely don't want to just snug this up as tight as you can with a big wrench. In my experience, you really just turn it in until the rattling has barely gone away, and then double check for any rattle at operating temp and do a final eighth of a turn if need be. You can check it every now and then, but mine's been working trouble free for months now with no leaks, no backing out, and no adjustment needed.

Ive posted that on here quite a few times over the years,just never added the pictures.
Thanks for the pictures.
Forgot the stop/jamb nut.

You did a great job there. I'll add a couple things for consideration in case you don't trust adjusting manually. I've never had a bit of trouble with that auto tensioner that was subject of many a horror story, but have compared it side by side to the early manual tensioners as used on 77-78 KZ650/1000. The advantage to the manual one was more reliability obviously, but the big deal to me was the fact the manual has a much longer adjustment range so on a high mile engine even if the automatic one is functioning correctly, it may get to the end of its adjustment range before the chain is even worn resulting in noise ect. Best bet is to get a manual tensioner off a 77 or 78 KZ650 or KZ1000 and bolt it on. Of course manual tensioner on these bikes is still fully automatic in adjustment, but the difference is to initiate adjustment is done manually by loosening then retightening the bolt. Easy to work the manual tensioner and reliable as a rock.

On the old style adjusters it is important to adjust it while the tension is in the front of the engine. To do this, you must rotate the crank forward to a point it won't move back on it's own. You should hear a click when the plunger moves forward. Sometimes the rollers get sloppy and the spring becomes weak so noise can still be heard.
Steve

On my stock manual adjuster (78 Kaw 650) I replaced the spring (NOS Kaw) and it has a lot more tension to it guessing 40-50% more, forget exactly but it was a good 1/2 inch longer too so the stockers sag over all those years.

Thanks for all the great pointers on this thread, I wanted to add one more caveat that applies to mounting a manual tensioner. Maybe only someone as new as me would be at risk of this mistake, but anyway, you want the tensioner on the loose side (i.e., shaft not extended *too* much) as you attach the assembly back onto the engine. If the shaft is already out too far when you go to mount the thing, you'll put excess pressure against the cam chain when you tighten up the mounting bolts. During mounting, prior to adjusting, there shouldn't be much push back from the cam chain on the tensioner shaft, and you should be able to push the assembly flush against the case by hand.

Hope that helps someone out there!

Phillip Pippenger

I the manual it says to load the plunger all the way back. Once installed on both kinds, you loosen the lock bolt and should be able to hear a "audible click" as the plunger moves back in. The problem with the old style manuals is the rubber padded foot will get hard and can come apart. The rubberized components were for noise reduction. In my book, they just wear out faster.
Steve

Got to be careful, tightening them manuals. Like a drive chain, some cam chains have a high-low spot.
I used to losen early stock tensioners. rotate engine a few times. Bring it up to TDC then tighten.
I use the nice billet one made by That Machinist Dan out in the midwest. who sells nice stuff on ebay.
Speaking of ebay! I had tried 2-3 times to sell this 79 auto adjuster for $9.99. No one bought it?
I still have it somewhere. here is the ebay picture I used.