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Chain Cam Tensioner Failure (BUT WHY?)

Randall K. Wilson

Randall K. Wilson

Junior Member
I know there has been a lot on this forum about the 88 Twin Cam Engine Cam chain tensioner failures etc. (I hope the forum Town Fathers let my post run)
Here is what I am intrigued about. What actually is the cause of this? Your imput would be educational and informative and personal as well.
Having read many accounts it seems to me the oddity is that it is the randomness of it. Or no exact amount of mileage on the machine when these wear out. Case in point...I talked to a gent that just checked out his '04 Roadglide with 54K miles. His tensioners were only half worn out. Yet at 30K miles my brothers '03 Ultra's were shot and had to be fixed on the spot.
With the history being what it is, could this be the cause. In production back then some actual chain cams got out that had perhaps "minute burrs" on them? Hence the rub plates would wear quicker....Or Perhaps the material the rub plates were made of a poor quality?
Working in Manufacturing many years...even the best quality control system is alway less than perfect...Just ask Toileta or Firestone tires to name some more resent. Companies can try to do their best...yet "things get out".
Hope to hear some feedback and personal views and observations on this matter of "CAUSE", of failure?????
 
Many of the causes you listed are in fact contributing factors. The first is the composition of the tensioner pad being inadequate for the job,next would be the chain itself and the rough edges on the surface that wears on the tensioner. I'm sure that the lubrication and style of riding would figure into the equation too but it sure is odd that some tensioners have gone in under 20K and others last 70K .
 
What about spring tension? Did it vary from bike to bike?

Did Harley figure something out around 04 and not make it public. Mine 04RK were not worn at 30K, but pitted. Almost looked heat related.
 
Some think the spring tension was a problem with wear too , they may be on to something. The pitting is pretty much normal too.
 
My bike developed a very noticeable whine, but by then the inner tensioner was all the way to the metal
 
Wayne R said:
when they start to go or become badly worn are there any warning signs you might get?
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You can watch your oil for yellow particles, or cut open your oil filter and inspect. I have not tried either of these methods, but have read about them. b

If you have a 99-06 you just about have to address it. At least check them for a piece of mind. There is a good step by step procedure. I found it on another forum. I will post it, if it is okay.
 
Some Mechanics I've talked to feel that long periods of slow speed riding and extended periods of idleing on extremely hot day's may make them wear quicker. Because of the higher oil temps during that type of operation. Like some police bikes are used in a city. I think maybe the guy's that said burr's or rough spots on the chains might be the problem could be onto something. As well as the the amount of sring tension. I have seen some pairs of tensioner shoes that were replaced, where one shoe was hardly worn at all and the other was shot and worn to the metal. I wonder if anyone has done any research into the amount of wear with bikes running synthetic oil as opposed to dino? Of course the riding habit's of different people might make that harder to figure out.
 
cowboywildbill said:
Some Mechanics I've talked to feel that long periods of slow speed riding and extended periods of idleing on extremely hot day's may make them wear quicker. Because of the higher oil temps during that type of operation. Like some police bikes are used in a city. I think maybe the guy's that said burr's or rough spots on the chains might be the problem could be onto something. As well as the the amount of sring tension. I have seen some pairs of tensioner shoes that were replaced, where one shoe was hardly worn at all and the other was shot and worn to the metal. I wonder if anyone has done any research into the amount of wear with bikes running synthetic oil as opposed to dino? Of course the riding habit's of different people might make that harder to figure out.
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i think it's quite obvious that no one has the exact answer, but I do believe that all the reasons could be contributing factors. As far as synthetic oil goes all I can say is that my ride has 47000 miles on it and has had synthetic oil in it since first oil change and my tensioner shoes shoe very little wear, however most of my miles are road miles, very little around town riding.
 
It's a toss of the dice...... cam tensioner material, chain smoothness, oil, and use. all likely play a part in the failure.
I replaced my tensioners this January.... 50,000 miles, and the shoes were less than 40% worn.... but... I was there.... why not replace them. Sure I could have left them in place.... but the voice in my head, would keep reminding me, they were worn.... cheap enough to do....and, as I said... I was already there...
 
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