Question re: 426 Cam Chain Tensioner


8 replies to this topic
  • MNellis

Posted April 15, 2005 - 06:59 PM

#1

I've seen it posted several times now that people have replaced their cam chain tensioner for one reason or another. On poster even mentioned his tensioner went bad.

My question is, "how can the cam chain tensioner go bad".

I'm putting my 426 back together after a total rebuild including crank, crank bearings, new cylinder, piston, rings, intake valves and exhaust cam.

Notice I didn't mention cam chain or cam chain tensioner. Before installing the cam chain tensioner the other night I took it apart to ensure it was clean and working properly. I'm no expert on cam chain tensioners but I could not see how one could wear out. The spring is in good shape and there is nothing else in there to wear out. A sleeve, a threaded rod and a piston along with a retaining clip and retaining washer.

The manual does not talk about dis-assembly and re-assembly but it doesn't look like there is much to it. Anyway, when putting it back together I found I could not get the tensioner to extend enough to put tension on the cam chain. I inspected the cam chain carefully and found it to be extremely worn to the point that each link/pin had several thousdands play. A few thousdands by itself is not much but when multipled by a hundred links or so it adds to up to quite a bit.

I've got a new chain on order but I did not replace the tensioner.

Can anyone convince me of something in the tensioner that can go wrong and why I should replace it?

  • Guest_BrandonV_*

Posted April 16, 2005 - 07:27 AM

#2

The only convincing I would need is that you just spent top dollar rebuilding your bike and why chance it on a $25 part?
My 426 is getting the same treatment yours just did and I ordered a new tensioner even though mine seemed to function perfect. Cheap insurance!

  • 02YZ426

Posted April 16, 2005 - 07:57 AM

#3

Ya, just change it for piece of mind. If that old tensioner skips a couple teeth when your on the power, then so much for your new rebuild. Once the cam chain skips too many teeth due to the tensioner failing then you are going to be pi$$ed you didn't change it.

  • Matt96xr6

Posted April 16, 2005 - 11:42 AM

#4

The only part that really wears is the spring to hold tension on the foot against the guides. Other than that, if it is broken in any way.

FYI, get the unit from the 450s. They are shorter and give you more room to rotate the carb without removing it for cleaning and jetting.

Visit the ThumperTalk Store for the lowest prices on motorcycle / ATV parts and accessories - Guaranteed
  • MNellis

Posted April 16, 2005 - 01:03 PM

#5

Ya, just change it for piece of mind. If that old tensioner skips a couple teeth when your on the power, then so much for your new rebuild. Once the cam chain skips too many teeth due to the tensioner failing then you are going to be pi$$ed you didn't change it.


You see, that's my point, except for the spring, I don't see how the tensioner can fail. Since those old tensioners don't have teeth to skip I doubt that's going to happen. As long as the spring is in one piece then it looks to me like the tensioner is working fine.

Piece of mind can be pretty expensive sometimes. Should I just change out everything whose operation I don't understand. Nah, I don't think so. I'd be changing out wheel hubs for piece of mind. I wouldn't want one coming apart on the next jump and ruining my day. :naughty:

Based on the answers I got (or lack of answers), it seems like the tensioner is not a consumable part anymore than the kickstart lever or shift drum is a consumable part that needs replacing just....."because".

I think I'm going to live on the edge and not replace the tensioner. :naughty:

Thanks

  • 02YZ426

Posted April 16, 2005 - 01:46 PM

#6

You see, that's my point, except for the spring, I don't see how the tensioner can fail. Since those old tensioners don't have teeth to skip I doubt that's going to happen. As long as the spring is in one piece then it looks to me like the tensioner is working fine.

Piece of mind can be pretty expensive sometimes. Should I just change out everything whose operation I don't understand. Nah, I don't think so. I'd be changing out wheel hubs for piece of mind. I wouldn't want one coming apart on the next jump and ruining my day. :naughty:

Based on the answers I got (or lack of answers), it seems like the tensioner is not a consumable part anymore than the kickstart lever or shift drum is a consumable part that needs replacing just....."because".

I think I'm going to live on the edge and not replace the tensioner. :naughty:

Thanks




Well, there may not be "teeth exactly" to skip but but there is some kind of locking mechanisim in there that can fail...I'm sure if you do a search you will find threads about these things failing do to age...... In fact I have read the posts. I guess if you dont care about the possible damage that can occur, then dont worry about it. I didn't change mine either, but I likley should have.

  • MNellis

Posted April 16, 2005 - 05:07 PM

#7

Well, there may not be "teeth exactly" to skip but but there is some kind of locking mechanisim in there that can fail...I'm sure if you do a search you will find threads about these things failing do to age...... In fact I have read the posts. I guess if you dont care about the possible damage that can occur, then dont worry about it. I didn't change mine either, but I likley should have.


I think my point is being missed here. Everything fails, it's just a matter of when and how, that's what I'm trying to determine here. It's not that I don't care about possible damage resulting in a cam chain tensioner failure, of course I do. After spending maybe close to $1500 for all the parts along with a bunch of time in doing the work, who wouldn't?

My original post asked, "how can the cam chain tensioner go bad". and I was hoping to hear from those that might have some direct experience with failed tensioners. Either those folks don't care to reply, didn't see the question or no one has actually seen/experienced a cam chain tensioner failure first hand in the field. If no one has any direct, first hand experience, then that's fine and I'll take my chances based on what I see as a pretty indestructible part. My experience with cam chain tensioners from 30 years ago (yea, I'm an old guy :naughty: ) was that they had parts in them they occassionally failed and easily wore out.

As you can see in the picture, other than the spring (which is in good condition) there is nothing to break or wear out on these things, at least none that I can see.

Anecdotal replies like, "you should", "I heard", "some people have" etc., etc. don't do much good without some facts and evidence to back them up. Like most of us, I participate in many different motorcycle and aviation related message boards. Much of the advice and knowledge we get from these boards is excellent and beneficial but much of it is dispensed by those without experience.

I guess I'm just looking for a free education that will help me (and possibly others) make an informed, rational decision. Heck, you can't get any decent information from the dealers because the few that I've visited either don't have it or don't know where to get it. The smaller shops that have the older, experienced mechanics want to do the work for you and are unwilling to dispense the information (can't blame them for trying to stay in business I suppose) and the shop manual is useless when it comes to this particular component.

My only option then is to search the net and, barring any luck getting some information, dig into the part myself and try to figure out what makes sense. It looks like the latter is turning out to be my best option at this point.

So be it. When I'm done I'll post as much information as possible and take on the role of educator myself.

I'm glad to do it.

Here is the part we're talking about.

I appreciate everyone's good intentions at dispensing advice.

Posted Image

  • Satch0922

Posted April 17, 2005 - 08:44 AM

#8

like Matt said...replace it with the 450 unit and your good to go. Replace the cam chain while your at it. Those two pieces are the last thing you should gamble on.

  • skthom2320

Posted April 17, 2005 - 01:01 PM

#9

I think my point is being missed here. Everything fails, it's just a matter of when and how, that's what I'm trying to determine here. It's not that I don't care about possible damage resulting in a cam chain tensioner failure, of course I do. After spending maybe close to $1500 for all the parts along with a bunch of time in doing the work, who wouldn't?

My original post asked, "how can the cam chain tensioner go bad". and I was hoping to hear from those that might have some direct experience with failed tensioners. Either those folks don't care to reply, didn't see the question or no one has actually seen/experienced a cam chain tensioner failure first hand in the field. If no one has any direct, first hand experience, then that's fine and I'll take my chances based on what I see as a pretty indestructible part. My experience with cam chain tensioners from 30 years ago (yea, I'm an old guy :naughty: ) was that they had parts in them they occassionally failed and easily wore out.

As you can see in the picture, other than the spring (which is in good condition) there is nothing to break or wear out on these things, at least none that I can see.

Anecdotal replies like, "you should", "I heard", "some people have" etc., etc. don't do much good without some facts and evidence to back them up. Like most of us, I participate in many different motorcycle and aviation related message boards. Much of the advice and knowledge we get from these boards is excellent and beneficial but much of it is dispensed by those without experience.

I guess I'm just looking for a free education that will help me (and possibly others) make an informed, rational decision. Heck, you can't get any decent information from the dealers because the few that I've visited either don't have it or don't know where to get it. The smaller shops that have the older, experienced mechanics want to do the work for you and are unwilling to dispense the information (can't blame them for trying to stay in business I suppose) and the shop manual is useless when it comes to this particular component.

My only option then is to search the net and, barring any luck getting some information, dig into the part myself and try to figure out what makes sense. It looks like the latter is turning out to be my best option at this point.

So be it. When I'm done I'll post as much information as possible and take on the role of educator myself.

I'm glad to do it.

Here is the part we're talking about.

I appreciate everyone's good intentions at dispensing advice.

Posted Image



That's a lot of effort for a $25 part. But if you have the time and inclination - go for it! :naughty:





Related Content

 
x

Join Our Community!

Even if you don't want to post, registered members get access to tools that make finding & following the good stuff easier.

If you enjoyed reading about "" here in the ThumperTalk archive, you'll LOVE our community. Come join ThumperTalk today!

The views and opinions expressed on this page are strictly those of the author, and have not been reviewed or approved by ThumperTalk.