OEM Chain Tensioner vs Manual?

650ed wrote: I guess that depends a lot on which stock tensioner the bike has. Kawasaki made a variety of changes, but not necessarily improvements, to the tensioners over the years. The early tensioners, like those that came stock on the 1977 KZ650, cannot slip since they must be set manually and then locked in position using a bolt and locknut. Some, if not most, of the later ones actually can slip since they are the "automatic" wedge type. I would be very hesitant to trust them having read several serious complaints on their reliability. Ed

Where have you read about problems with the wedge type tensioner? I really haven't seen it anywhere.

There was a recall on them on the early bikes.
Steve

SWest wrote: There was a recall on them on the early bikes.
Steve

The J engine with the "wedge" tensioner came out in '81. I really think the advertised danger of a tensioner backing up pertains to hydraulic tensioners. I've yet to hear an example of a failure with the wedge design.

What recall are you referring to? The only one I've heard of on my bike was the oil pump.

My neighbor was a dealer in CO. He told me when they first came out, most of them failed. A lot of their work was warranty work for the factory along with changing the steel valve guides they had been using. High oil consumption. He called it a quiet recall.:dry:
Steve

No eBay APP ID and/or Cert ID defined in Kunena configuration

VTEC wrote:

daveo wrote: I changed-out the stock tensioner to the APE manual version several years ago, after discovering that the pressure that stock gizmo exerted was sufficient enough to severely distort the rear chain-guide, causing it to bulge-out at the sides and heat-set in that shape over time.
I've been inside this engine a few times since that APE was installed, and found minimal distortion if any. And the motor keeps on running...just as quiet as can be.

I don't think the tensioner was the cause of your problem. A buddy of mine worked on the CHP bikes with J engines that reach 200k miles, and he never saw a problem with the OEM automatic tentioner.

Please See:


If you examine the listing photos of the rear guide, you will see...the bulge that I'ma talk'n bout. :pinch:

What else coulda-woulda cause that to happen

I don't know about a recall, but according to Larry Cavanaugh with the cross wedge type tensioner the main plunger can slip backward even under running conditions if the cross wedge spring starts to become weak. Larry knows more than most about the KZ engines. See link below for details. Ed

www.kzrider.com/forum/2-engine/516550-va...uto-tensioner#516860

I don't think there was a recall. A recall in 1980? That idea was not thought of yet on motorcycles. At that time motorcycles were not even considered as motor vehicals to put any consideration into safety. The stupid fuse problems with melted fuses commonly should have been the major recall if one happened. The manual tensioner used through 1978 worked fine. Can't see any need to ever worry with it. The 79 era auto tensioner had some bad reputation as did the later type, but both worked pretty well in my own experience. One problem the auto tensioner had over the manual was much less travel available on the plunger. I had a manual and automatic KZ650 side by side, and the manual had like 2x the available travel of the pushrod.

Thanks. First I've heard about a weak spring causing a problem. But again, 35 year old springs don't have nearly the tension of new. Same applies to the bulge in the rear guide. 35 year old plastic is bound to deteriorate.

So here's where I'm going. New OEM auto-tensioner and springs. Drilled and tapped a lock bolt behind the pushrod. Once top-end assembled and horizontal wedge and spring installed. Rotate the engine a few times to position the pushrod. Then turn in the lock bolt until it touches the pushrod, back it out a 1/4 turn, and secure the locknut.

Now I have an OEM auto-tensioner working as designed, and a failsafe lock-bolt to eliminate any chance of a backup enough to jump time.

Looks good.
Steve

Here's a ZRX tensioner: www.partzilla.com/parts/search/Kawasaki/...TENSIONER/parts.html

Again, continuous spring tension against the rear guide. Not hand tight, 1/4 turn back, and a loose chain.

Not sure, but it looks like it may have a toothed one-way check on the pushrod to prevent backup. That's what Honda car engines use on their oil pressure fed hydraulic tensioners.

The toothed design eliminates any chance of a backup.

daveo wrote: If you examine the listing photos of the rear guide, you will see...the bulge that I'ma talk'n bout. :pinch:

What else coulda-woulda cause that to happen

Look at the bottom of the page: kzzone.com/sprockets.html

APE sells an HD rear guide to solve the problem you're talking about. Again, I think age is the big factor.

VTEC wrote:

daveo wrote: If you examine the listing photos of the rear guide, you will see...the bulge that I'ma talk'n bout. :pinch:

What else coulda-woulda cause that to happen

Look at the bottom of the page: kzzone.com/sprockets.html

APE sells an HD rear guide to solve the problem you're talking about. Again, I think age is the big factor.

Definitely, age plays a part...probably as big a part as heat. The two together must surely contribute to brittleness of the rubber/anti-friction components that the oem guides are/were molded of.
The APE guide may be a solution to the problem of friction-wear, but whether they help with the age/heat factor or not...

Is it possible the bulge issue has more to do with the oem tensioner wedge design which only increases pressure to eliminate slack in the chain...only released when the unit is manually disassembled per FSM instructions.

The APE (and like copies) tensioner maintain that slight amount of slack always, which I believe minimizes stress on the entire cam-drive system.