Tell Me Why You Will Keep Your Auto Cam Chain Tensioner (2010)

Anyone still running the spring loaded, too damn tight, cam chain tensioner that plans on NOT reverting to stock?

I am still stunned, and angry with the damage done to my intermediate gear shaft and locating housing.

Wish I had never fallen for this gimmick.

Still running them in both my bikes, and can see no reason tho change! I don't set them up tight when installing them...leave a little bit of slack so the spring has some movement, and it works fine. The only mod I did was to weld the pin in rather than rely on the circlip. Been in there for 4-5 seasons and haven't had a problem!!

Seeley920 said:

Still running them in both my bikes, and can see no reason tho change! I don't set them up tight when installing them...leave a little bit of slack so the spring has some movement, and it works fine. The only mod I did was to weld the pin in rather than rely on the circlip. Been in there for 4-5 seasons and haven't had a problem!!

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So you can adjust the pressure? highdesert, do you believe yours was set up tight?

1) I installed mine some ten years ago, maybe 9000 miles ago.
I installed it exactly per the instructions, and I even called by phone to verify that my concern about the cam chain feeling quite tight was "normal".

I was not aware that there was an alternative method to installation that permitted setting the tension any differently as the spring loaded slipper
is what sets the constant tension.


2) I also thought everything in there was just find and dandy all these years, just like you may think so right now.

How would you know right now as I type that there is no damage being caused by having it in your motor?

The only way to know is by doing what I did, and that is to get in there and remove everything in order to get to the intermediate gear shaft and it's
locating holes in both the inner and outer timing covers.

And THAT is where I was shocked to see the damage done, and now the expense of the repair.
See my earlier post for more detail of the damage.

In short, you do NOT know right now that you are not suffering the same damage that I, and others, have from a TOO TIGHT cam chain.

Assume all is fine, but to do so only because you are not aware of the damage being done is perhaps ignorance is bliss.

Don't get me wrong guys, I am speaking only from direct personal experience, and I am not the only one.

I am NOT saying that because it happened to me, that it must surely be happening to you.


BUT, I have posted this to make everyone aware, an alert. Do with it what you will.

FWIW mine are race motors and are regularly stripped....3-4 times a year and so far there is NO damage! Like I said, I didn't push the tensioner up too hard, so that there is a little bit of free movement in the spring....also turn the motor over and observe tight spots....don't forget you adjust a chain at it's tightest spot as they tend not to wear evenly! If you adjust it at on eof the loose spots, then there will obviously be a point where it is too tight.....primary/cam/final chains, it makes no difference, same rule applies!!

Seeley, you are fortunate that have the time and race bike inclination to check it 3-4 times a year.

Respectfully, I believe you would be the exact opposite of the rest of us who leave it in for years and years.

In addition, your knowledge base in setting it at the right point in the chain initially is superior , likely, to the rest of us non racer types.

I am glad it is working out for you.

There is a man in OZ name Kelly Cork near Brisbane. He makes a tensioner from a Nissan cam chain tensioner. Many have been made and used. They press the tension from the inside out not the outside in. No modifications to case at all. They any change the chain tension in .030 increments so they never over do the tension. They are much more thought out and somewhat better priced than the other one as well. I have posted about this before. No one cares.

And how does one go about contacting Kelly Cork? Does he have a representative in the U.S.?

When I met him he was doing 20 or so for a guy in Canada. I don't know who and he was saying that doing so many at once was kind of a pain. He also said that the order came in at least once a year. I will check into it but he is not an internet kind of guy. I will try. It was Reg pronounced (Redge) from this board years ago who took me around to see him one day. Reg is not on the board any more. Reg knew many amazing gentleman who built incredible machines around the area. Best riding I have ever done in the hills all about and great bars too.

I'm going to have a look at my automatic tensioner once I get all the fiddling done after just putting the bike back together (it started on the first half hearted kick - you gotta love 'em). From your experience it sounds like too much of a good thing. I've probably got 15-20,000 miles on mine. I'll let you know what I find.

Greg

As with all the responses here, my one experience means nothing, except my one experience.

Regardless, My RMA was installed by a professional who was impressed with the design and planned to install it on his future rebuilds.
Mine's been on for 6 years and 12000 miles including an Iron Butt 1000 miles in 24 hours, a 7 state 3200 mile scenic Seattle to Torrey and back at the '07 Rally, and then just some of the usual Nortoneering. Had the cover off recently, and everything looks dandy.

Statistically, people who have an unsatisfactory experiences make their issues know about ten times as often as those with satisfactory experiences. I just want to make sure some of us 10 percenters make ourselves known.

On the other hand, I'm equally content to know that I'm just one lucky SOB!

See y'all at Lumby

Carey

Gday All,
In my quest to find parts to make my Commando motor maintenance free (as possible), I contacted Kelly Cork some 6 months or so back to see if I could buy the tensioner from him. He told me that he no longer makes them! Now Im thinking that the cost of new timing chain plus auto tensioner might be best spent on Jims GEARS?
The link below is worthy of a read aswell.

http://britiron.com/dc/20/390/20-1/

Rgds Foxy

Vertigo said:

Statistically, people who have an unsatisfactory experiences make their issues know about ten times as often as those with satisfactory experiences.

Carey

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I agree with the above line so I have to wonder why I have seen a number of posts, etc. relating to tensioners failing but absolutely none dealing with premature engine wear even though they've been around for a while. Since I needed an oil change anyway and my points seal was weeping I thought why not have a look and see how mine was doing. Everything looks great 2000 miles after installation so I figure since I don't rev it to the suggested red line and until I hear of more evidence I'll leave well enough alone and monitor the situation.

Guys, I too was under the same impression as those who are content with their spring loaded tensioner.

I wish to point out that you cannot see any damage being done simple by taking off the timing cover and looking inside.

The same applies to just continuing to ride along with nothing bad happening.

BUT, and here is the problem.

My spring tensioner also "looked good". But it was NOT. Because you CANNOT see how the too tight tension is gradually causing the intermediate gear's locating shaft to be pulling forward and also in and out, right to left side of back, as time goes blissfully on.

I am now paying to have the shaft's locating holes, in BOTH the inner and outer timing covers, filling in with heat welded metal to restore the shaft's ability
to keep the intermediate gear in it's proper location.

In fact, the forceful movement of the too tight shaft wore a full 150 thousand of an inch into the outer timing cover, and ob-longed the locating hole in the inner cover.

Again, you may think all is well because you cannot see what is happening. Just a strong heads up from one who has seen, and is paying for, the damage.

Highdesert, My 2 cents. I have seen this damage before and agree, I wouldn't use one .
To fix the hole In the main engine case I would suggest boring it oversize and installing a bushing instead of welding. If you weld there you will distort the main bearing bore and any other surfaces around it. The case will never be as strong again in that area because of damage to the heat treatment from the welding heat. Welding on the side cover shouldn't cause a problem. Jim

Thanks for your comments, Jim.

I may have wrongly represented the repair job to the inner cover hole.

My guy told me he fixed the outer cover by installing a 175thou spacer in that cover's hole.

He fixed the inner shaft hole's oblongness by, if I remember correctly, by using a high temp MIX of some sort to build a little material in that area.

He is satisfied with the repair and with going back to the stock cam tensioner, is convinced no more damage will be done.

I feel that the spring loaded tensioner is a "beautiful theory, but ravaged by a gang of brutal facts".

Personally I've always used the hardened steel slipper, I've never used an auto adjuster and probably never will.

However, I'm puzzled how the auto chain adjuster can create enough force to elongate the two holes, I mean good grief the alloy is under compression. The only conclusion I can come to is perhaps the intermediate gear seized onto the shaft or the shaft was not held in the cases tight enough, or indeed the tightness of the chain generated too much friction in the gear bush and the shaft started to rotate.

Have you any photos ?

Best of luck with the repairs,
Cash

cash said:

Personally I've always used the hardened steel slipper, I've never used an auto adjuster and probably never will.

However, I'm puzzled how the auto chain adjuster can create enough force to elongate the two holes, I mean good grief the alloy is under compression. The only conclusion I can come to is perhaps the intermediate gear seized onto the shaft or the shaft was not held in the cases tight enough, or indeed the tightness of the chain generated too much friction in the gear bush and the shaft started to rotate.

Have you any photos ?

Best of luck with the repairs,
Cash

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The problems happen if there are tight spots and loose spots in the chain of large enough magnitude. This can be caused by an unevenly worn chain or sprockets that aren't concentric. [few of them are] The auto adjuster takes up the slack in the loose spots and then when the chain or sprocket rotates to a tight spot it puts a very large load on the bushing in the pinion gear because the adjuster cannot back up. This causes the bushing to stick momentarily to the shaft and rotates it even if it was tight in the case to start with.
I don't think this happens to a very large percentage but the potential is there. I would suggest replacing the chain periodically to help avoid damage. Jim

Kommando thanks for the info on spring cutting I wont be doing that.

Ian James said:

Kommando thanks for the info on spring cutting I wont be doing that.

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Kommando hasn't posted in this thread - what are you replying to?