Yosh uses stock cam chain tensioners

[OB_WARBIRD]

SlowHand, that is the most sensible explantion of this problem I've heard yet. Not enough spring tension after it extends out a certain amount. Sounds like you have a good technician there.

Thank you for the informitive post.

 

[OB_JRBusa]

obvious reason for using the stock tensioner it to reduce maintenance time that a manual might mandate. It would be too time consuming to have to adjust the cam chain during an event. Normal running should not facilitate frequent adjustments however running wide open for hours will obviously cause more signifigant timing chain stretch causing the need for more frequent adjusting. Self adjusting means one less thing to have to worry about in an 8 hour event.

 

[OB_Gary Evans]

And???

 

[OB_Cisco San Jose]

I bet they replace it after every race!!!!!!!

 

[OB_NumbNuts]

so, we know from that it will last 8 hours...........actually, we know that THEIR one lasted 8 hours. Wonder what it was like afterwards, and the spring stiffness compared to before. Now that would be interesting...........

Nuts

 

[OB_CaveDweller]

Does anybody know the reason Suzuki put the automatic cam chain tensioner on the Hayabusa instead of the manual option ?

It is hard to believe their decision was driven by anything other than reduced bike failures and reduced liability.

After inspecting the unit myself (yeah, you got me scared now too) it looks to me like the automatic tensioner can maintain a constant (or better approximation to it) chain tension at varying RPM while the manual tensioner cannot. I would love a Suzuki engineer to get on-line and tell us the design/performance trade-offs involved in variable vs. constant cam chain tension.

I don't presume to have the answer here, but there must be some performance benefit if the Yosh guys use it. I see on this board that the manual tensioner is an easy replace, easy to adjust item - so what does Yosh know that we aren't considering ?

 

[OB_CanuckBusa]

I've gone with the manual anyway. But there are a couple aspects to spring tension. First, and 'ideal' spring maintains the same tension throughout its entire range of travel (spring rate). Many 'real' springs exhibit close to this behaviour. Second, I suppose a spring can fatigue or wear, and then have less tension than before. But again, I would suspect that the spring would maintain a fairly constant spring rate. But any spring that is extended past its range would have no spring tension (or very high spring tension). I am not exactly sure what Slowhand is referring to. But anyways, the point is moot for me. I will run manual.

 

[OB_CanuckBusa]

Cavedweller, you raise an interesting point. Perhaps you could write a letter to Suzuki and ask for the tech details. I was told that if I wrote in, and asked for a technical response, I might just get one. I intend to do so myself, eventually, I'm just trying to get my bike back on the road so that is my number one priority right now.

So Yosh's tensioner lasted 8 hard hours. That's cool, but doesn't prove that the auto is better than manual. Doesn't prove much of anything.

I had no desire to put a manual in, but here is my logic.

1) The odds of a failure of the auto unit are small, but not vanishingly small.
2) I have no warranty.
3) The cost and time to repair the bike is large.
4) I have already been without my bike for 3 wks this summer (through no fault of my bike).
5) The manual is relatively inexpensive and has been used by lots of other people.
6) The manual can cause a problem if it is installed or adjusted improperly. But I am going to trust my wrench on this one - I have a feeling they have installed and adjusted a few of these before.
7) Conclusion: Put in the manual and get back to riding.

 

[OB_SlowHand]

When we replaced my tensioner with a manual a couple of days ago, my mechanic observed that the stocker is one of the older designs.

It is a screw type that works under spring pressure, and he said that the problems with those usually arise when the adjustment gets out near the half-way point and the spring has lost tension. It stops adjusting and if you don't notice the additional noise and change it, disaster is imminent. Apparently they work fine for a short period of time, hence Yosh's use makes sense.

My wrench says that he likes the ratchet type tensioners better, and even likes the hydraulics, except on ultra high rpm engines. He prefers the manuals over every other type, for long term use.

I'm not setting my mechanic up as the ultimate authority, but he's been doing my bikes, of various makes, for years. He also is independent and can tell the truth without getting fired, unlike some Suzuki mechanics.

If I had Johnny Cheese or someone like him at my local Suzuki dealer, I might take a chance and rely on my warranty. I don't, and most of the rest of us don't.

I'm not about to have my bike sitting at the dealer's for weeks with a destroyed engine while the dealer and Suzuki play the "after you" game with each other. If you guys are happy with that act, it's fine with me.

 

[OB_fshaia]

I e-mailed Doug at yosh and he says they use the stock (updated) on their 8 hour Suzuka race bike ?

 

[OB_CaveDweller]

JR

A good thought, but your obvous answer isn't born out by folks on this board. An 8 hour race, (even at 180 Mph average) is only 1440 miles. The manual is good without adjustment (according to posts) up to 3000 miles (an oil change). Also, the automatic has failed for some (according to posts) at less than 500 miles. So (by the statistics present from posts on this board) Yosh would be accepting a higher risk of failure to use the automatic, and not gain any service time benefit.

I am still gnawed by the feeling that there is a timing issue WRT variable chain tension (in manual use) and that perhaps there is a large performance advantage with a more constant chain tension (using the automatic).
(ie. the small changes in engine timing they would get with the manual unit that cost them a few HP).


[This message has been edited by CaveDweller (edited 04 August 2000).]

 

[OB_Velociraptor]

An automatic tensioner in good working order will extend to maximum when removed from the engine. When I compared the length of my manual tensioner to the automatic one that was fully extended, the auto one was roughtly 1/4 to 1/2 inch longer which tells me that at least on my engine with 4K miles, the auto tensioner was not close to fully extended when installed. What still bothers me and I have seen NO answers to is what exactly failed in the tensioners??? I am sure that failed tensioners replaced at a Suzuki shop are sent off to Suzuki for examination. Johnnycheese may or may not know exactly what is failing in the tensioners and he may or may not be able to tell us. He helps us a tremendous amount on these boards but if he started telling us stuff that Suzuki doesn't want us to know then he could get in some serious trouble. As I have already written in another post, my auto tensioner was working fine when I removed it and it would work fine out to max extension. Maybe there was a bad batch of springs that got out and these springs weaken to the point that they will not extend the tensioner rod enough as mentioned in this post. The truth is that noone knows for sure! I think I'm done posting about this because the well has run dry for anything more I could write that would be useful.

 

[OB_team_moos]

I too have had problems with the stock tensioner on my '99 600. I have been extremely displeased with the way Suzuki has chosen to deal with the matter. I am still without my bike and the summer is wasting away. Suzuki isn't trying to lend a hand at all. It seems that when it comes to warranty work, recall work, etc. ---Suzuki has taken the back seat. I am frustrated about the whole situation.

I held a protest at Laguna Seca in July of this year....some of you had probably seen me there with my car decked out in flyers. If you didn't, you can get all the information on my website at:

http://www.rider-info.com

The whole site is dedicated to the problem along with diagrams, pics, and other information. If we say/do nothing, customers in the future may experience simular problems to what I have experienced.

On my site, there is a link to an article that was run on a motorcycle magazine website. All the info is there. Don't hesitate to send me emails or ask questions.

Jonathan B. Moos
team_moos@hotmail.com
http://www.rider-info.com