Manual cam chain tensioner

The Zook tensioner still uses a spring. Make sure the engine is at TDC and loosen the lock bolt and nut located on the side of the tensioner instead of the rear like the APE design. The spring inside the tensioner does all the tensioning forcing the plunger forward just like an automatic. You then just tighten the lock bolt and nut. There is no ratchet system or pawl to keep the tensioner from backing off if the lock bolt comes loose. The plunger is a smooth bore design with one side machined flat for the lock nut. Sounds screwy but if done right it works fine. The Zook microfiche has a good breakdown of how it works. I really wish it was an automatic as I get tired of dealing with it!
More of a "semi-automatic" then. Kind of goofy.
More of a "semi-automatic" then. Kind of goofy.

I agree! Goofy, even though it works.

Edited by rmzpegger
Link didn't work.

There have been a number of designs for chain tensioners in the automotive world. A common theme is a spring loaded plunger that uses engine oil pressure as its primary pressure source, and a ratchet to prevent it loosening. When I first saw the design used by Yamaha on the YZF, my thoughts were that without the ratchet, it's entirely stepless, and that the means of preventing push back was so classically simple; you can't push a screw backward without turning it, and pushing on it won't turn it. Both very good things.

Still, something is clearly afoot here, and I still think the fault lies more with defective chains than with the tensioner. Perhaps in KJ's case it's different, with the extra spring pressure and such. It's a difficult problem to analyze.

Good thread. I was pondering a MCCT until reading the technical rebuttal given here against the stock units failing. It seems the manual unit is cheaper to make so the OEMs would use it especially if the auto units have a history of failing. However, lots of folks manufacture MCCTs and even engine builder on this site won't leave home without it.

Also I noticed a wide discrepancy on the correct procedure and frequency of adjustment of the MCCT. Folks on this site have recommended an initial rough adjustment then starting the bike and re-adjusting until the "noise" goes away. Not cool with that approach at all.

Thanks.

An alternative is the Pro-X cam chain, made by Borg-Warner

Do you think the Pro-X chain should be replaced as often as the OEM? If not, how long to you assume the Pro-X Chain should be replaced?

I have no way of determining how much, if at all, better the Pro-X chain is than the OEM YZF chain was spec'd out to be from the available info, so I don't know how long a good service interval would be. 100 hours of general use seems reasonable.

I have no way of determining how much, if at all, better the Pro-X chain is than the OEM YZF chain was spec'd out to be from the available info, so I don't know how long a good service interval would be. 100 hours of general use seems reasonable.

Would 100 hours be reasonable for the stock chain as well?

I replace the stock chain annually. Sometimes that's 100 hours, sometimes it's not. Racing MX or other closed circuit races is different from the desert racing and recreational riding I do, though, and it's harder on the cam chain.

Right, its kinda impossible to reccomend a certain amount of "hours" without a good understanding of the riders ability. By the way are the hour recomendations in the service manual for Pro riders, begginers or somewhere in between?

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!


Register a new account

Sign in

Already have an account? Sign in here.


Sign In Now