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General Category >> Rubber Side Down! >> Cam chain  theory
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Message started by bentwheel on 12/15/06 at 22:36:02

Title: Cam chain  theory
Post by bentwheel on 12/15/06 at 22:36:02

So a few guys  have blown a cam chain. In the last year or so there has been increased concern about what to do about the early demise of the Savage cam chain.  Is it true that it should be replaced before only 25,000 miles? Will frequent oil changes stem the premature wear? Should one use better quality oil? Should the engine be babied and not subject to an overrun? Is it just the nature of a single cylinder long stroke engine design that puts unusual stress on the cam chain?
Is there even validity to any of these theories?
Personally I don't think oil has anything to do with it. The cheapest oil available today is vastly superior to what you bought only five years ago, never mind what Suzuki R&D was testing with in the eighties when they designed this engine.
Try this theory on for size. Does Suzuki produce another single cylinder motorcycle  with a similar cam chain tensioner design that also is subject to early cam chain failure? Yes they do. The DRZ400 first produced in 2000 came with an automatic cam chain  tensioner that put too much tension on the chain. Suzuki improved the tensioner several times over the years until the problem was finally solved. Guys who have the early DRZ's have switched to an aftermarket manual tensioner   or adapted the one from a Hayabusa.
So could our automatic tensioner be ratcheting too much tension on our chains leading to premature failure?
By nature, an automatic tensioner is always seeking to unwind its spring and apply tension whenever it detects slackness. Also by nature long stroke engines  develop slackness or whipping of the chain due to its elongated length and longer power stroke. Imagine quickly bringing the Savage engine to red line then backing off abruptly causing the cam chain to slightly whip about in its cavity varying its tension only to be caught by the ratcheting tensioner looking to put a stranglehold on your already too tight chain.
So is the ACCT at fault?

Title: Re: Cam chain  theory
Post by SavageDude on 12/15/06 at 23:13:51

I don't know all the mumbo jumbo about cam chain; but if you riding between 45-70 mph and depend on what gear you're on, your rpm compare to auto almost double. Therefore, common sense would tell that the cam chain wear out twice as fast. I don't know the exact rpm/mph between MC and car.  I would give a more exact comparation. We have cam chain/ timing belt tensioner in car too. So it must be the relative RPM/MPH. Just my thought!

Title: Re: Cam chain  theory
Post by Rockin_John on 12/15/06 at 23:45:28

Now THAT's and interesting theory! Sounds very plausible too. Can't wait to hear what some gear heads have to say about it.

I've read that Suzuki addressed the known failure mode of the starter flange weakness on later models. What other known failure issues have been fixed? Has there never been an upgrade/change in the cam chain tensioning system?

Ahh... I've found the NHTSA's record of the Suzuki TSB (Technical Service Bulletin) for the DRZ models cam chain tensioner adjustment procedure change. Listed under "2003 Suzuki Motorcycle" in this search engine:

http://www-odi.nhtsa.dot.gov/cars/problems/tsb/tsbsearch.cfm

The plot thickens...

Does the Savage cam chain really fail prematurely?

Do we have a possible beef with Suzuki to issue a TSB on our engine's CCT?


Title: Re: Cam chain  theory
Post by Rockin_John on 12/16/06 at 00:07:58


SavageDude wrote:
I don't know all the mumbo jumbo about cam chain; but if you riding between 45-70 mph and depend on what gear you're on, your rpm compare to auto almost double. Therefore, common sense would tell that the cam chain wear out twice as fast. I don't know the exact rpm/mph between MC and car.  I would give a more exact comparation. We have cam chain/ timing belt tensioner in car too. So it must be the relative RPM/MPH. Just my thought!



I've thought about the revs the thumper turns in exactly the same terms as you... As a comparison/ratio of what my truck turns. It's a 6 cyl. and at 65mph in OD it's only turning a bit over 2K. Without a tach on my Savage, and not doing the math, I'd guesstimate your "double" figure to be pretty close. Even at that rate, what should be an acceptable failure mileage for the cam chain or even the tensioner itself? 15K? 30K? 50K?

Just my opinion, but I'd think an average of 25K-30K miles would be an acceptable preventive maintenance point considering we are discussing an air cooled single cylinder motorcycle. I might do mine earlier (15K?)  because I'm big, and I ride my bike HARD!

We do have to accept that most of the technology in the Savage is at least 20 or more years old. And even at that we don't even have the advantages of some known high mileage motorcycles from the past. No water cooling like the old "water bufflo" not even an oil cooler. Crude fuel and spark delivery systems by comparison to the EFI and EMS on modern day engines.

The Savage is what it is. Love it for what it is, improve it yourself, or...


Title: Re: Cam chain  theory
Post by Fat Bastard on 12/16/06 at 07:00:35

My Savage has now  just gone over 24900 miles (40000km) and I don't know if something has been done to the cam chain in its previous life's(2).  How difficult is it to see if it needs replacement or in worst case change the cam chain..

Fat Bastard.    

Title: Re: Cam chain  theory
Post by Kropatchek on 12/16/06 at 07:08:00

The problem of the camchain tensioner is that the tensioner guide and the chain wear-out untill the tensioner piston leaves the cilinder and breaks in 2 pieces and the spring falls down in the casing. This can happen anywere between 5 and 15,000 miles, depending of the driving if the rider.
There is Blue Thumper in the German forum who has designed a camchain tensioner which will extend the life of the system to approx. 30,000 miles.
Check out these links:
http://www.ls-650.de/Thumperbike/html/body_steuerkettenspanner.html

The pictures show you a NEW installed chain and guide, a worn to the limit system, jus before falling apart and the consequences after the tensioner has separated.

Link to the new system;
http://www.ls-650.de/Thumperbike/html/body_steuerkettenspanner_tbks3.html
And link to the post in the forum:

http://www.ls-650.de/community/forum/YaBB.pl?num=1165368220/15

with a schematic of the new design, not in detail. Norbert , the inventor, does not want to reveal all the details as he is trying to make a living repairing thumperbikes and protecting his invention from copycats.

BTW I have ordered the new design and will fit it to an engine with 12700 KM. This engine will be modified and installed next year. Will keep you posted.



Greetings
Kropatchek ;D



Title: Re: Cam chain  theory
Post by Fat Bastard on 12/16/06 at 08:22:05

Thanx.. I like threads with pictures. ..  I'll take a look at it...


Fat Bastard

Title: Re: Cam chain  theory
Post by SAMM on 12/16/06 at 10:44:18

As with any chain its not the constant speed of a chain thats hard on it....   Its the hard acceleration and decelleration and the snapping of the throttle that stretches the links.....    my 2 cents

Title: Re: Cam chain  theory
Post by Max_Morley on 12/16/06 at 21:34:28

Mine went about 25K miles and I feel it was because I like to run at lower RPM when not under a load so the load on the chain alternatively goes from one side to the other, at speed I would believe the load to be almost contast except when changing throttle positions.  I'd really like a long stroke to bore ratio thumper, they were the ones that had some torque. Max

Title: Re: Cam chain  theory
Post by azjay on 12/17/06 at 05:35:05


Kropatchek wrote:
BTW I have ordered the new design and will fit it to an engine with 12700 KM. This engine will be modified and installed next year. Will keep you posted.


are you saying that mod is available for sale? (sorry, my german sucks) if so, how and where can we get one?

Title: Re: Cam chain  theory
Post by Kropatchek on 12/17/06 at 05:46:11


azjay wrote:


are you saying that mod is available for sale? (sorry, my german sucks) if so, how and where can we get one?


Yes, it is.

Link to the prices and ordering:

http://www.ls-650.de/Thumperbike/html/body_preise.html

Offer is till end of year.

You need the top description for 269 Euro.
System, hardware, gasket and fitting instruction.

Press the "vorbestellung" button on the bottom of the page which opens an e-mail with adress. The guy understands English.

Greetz
Kropatchek ;D


Title: Re: Cam chain  theory
Post by Brewbrother on 12/17/06 at 05:53:59


azjay wrote:


are you saying that mod is available for sale? (sorry, my german sucks) if so, how and where can we get one?


here is a babelfish translation. I get the impression that the first item can be ordered on the website and the other items are inhouse repairs.

Open-loop systems clamping system TBKS 3


TbKs 3 completely with all attachments, coupler cover seal and fitting instruction.



269.00 €


TbKs 3 completely installation, oil inclusive with all attachments and filter change.



349.00 €


TbKs 3 inclusive installation and new open-loop system.


 
449.00 €


On all parts of the tension adjuster system I give a warranty of 10 years with appropiate installation.

$1.32 will buy a euro.

Title: Re: Cam chain  theory
Post by Kropatchek on 12/17/06 at 06:05:56

Thanks Brewbrother. Not being very helpfull, am I. Jus t lazy.

Greetz
Kropatchek ;D

Title: Re: Cam chain  theory
Post by Brewbrother on 12/17/06 at 06:14:10


Kropatchek wrote:
Thanks Brewbrother. Not being very helpfull, am I. Jus t lazy.

Greetz
Kropatchek ;D


no worries. ;D I like to help.

Title: Re: Cam chain  theory
Post by Reelthing on 12/17/06 at 06:39:51

Still trying to figureout what one gets for $355 price - do you have the kit in hand yet?

Title: Re: Cam chain  theory
Post by Kropatchek on 12/17/06 at 06:42:21


Reelthing wrote:
Still trying to figureout what one gets for $355 price - do you have the kit in hand yet?


Kit will be delivered in january, will keep you posted.
Greetz

Kropatchek ;D


Title: Re: Cam chain  theory
Post by vroom1776 on 12/19/06 at 09:19:41

This seems like something 10 or 20 of us ought to order all at once...  or one of us ought to buy 25 and sell them here...

Title: Re: Cam chain  theory
Post by Fat Bastard on 12/26/06 at 11:00:39

How much (how difficult is it) work is it to change the camchain and the tensioner.. Is it something that is pretty easy to do without complications or is it something that should be left to more skilled person?  (I have the Clymer manual and have done div. things to the bike and its still alive..)   How long should it take to change the chain? Novice - Expert  ..



Fat Bastard.

Title: Re: Cam chain  theory
Post by Phelonius on 12/26/06 at 11:33:20

Do these problems apply to a 2006 S-40 boulavard model or has Suzuki sorted this out by the time mine was produced?
Also does the 2006 DR 650SE suffer from this malady?
I have one of each.

Phelonius

Title: Re: Cam chain  theory
Post by bentwheel on 12/26/06 at 18:31:55

I don't think Suzuki has made any changes to the tensioner at any time during production. I think you are safe with the DR650, no problems there.

Title: Re: Cam chain  theory
Post by Kropatchek on 01/10/07 at 07:41:15

Update on the "Norbert" camchain tensioner.
http://www.ls-650.de/community/forum/YaBB.pl?num=1168393837

Short translation for those who are interested:

Price 146 Euros ( at 1.20 = 175US )

The oem tensioner can be used but the amount of travell will be extended. For those familiar with the inside of the engine, the brackets, laser-cut to 0.01 mm, are fitted to excisting tapped holes in the crankcase.
Normal wear on the chain will have to replace the chain at 20k Km. With this layout the expected life of the chain is estimated at 50 to 70k Km.
The adjustment with removed clutchcover has to be made around 20k and once adjusted the tensioner can not fall apart in 2 pieces anymore. He will make 15 sets.
Contact or post if you need more information
Greetz
Kropatchek ;D


Title: Re: Cam chain  theory
Post by Kropatchek on 01/10/07 at 07:48:19

These are pictures of the "Extended Version"

http://www.ls-650.de/community/forum/YaBB.pl?num=1165368220/15#15

Scroll to last post.

This has the shockdamper at the top and has to be adjusted on the bottom every 3000 Km.

Accoording Norbert this can be done without taking the clutchcover off although I don't know jet how that works.

FYI 3 sets are still available

Greetz
Kropatchek ;D



Title: Re: Cam chain  theory
Post by KenGLong on 01/10/07 at 13:31:16


Kropatchek wrote:
These are pictures of the "Extended Version"

http://www.ls-650.de/community/forum/YaBB.pl?num=1165368220/15#15

Accoording Norbert this can be done without taking the clutchcover off although I don't know jet how that works.


There's a picture on that page that looks like a bolt head coming through the cover. If it's anything like an old Honda GL500, you just loosen that bolt and the cam chain tensioner "slips" into a tighter position and takes out the slack in the chain. You then tighten the bolt and you're good to go for another 3000kms.

Ken

Title: Re: Cam chain  theory
Post by Kropatchek on 01/10/07 at 15:42:11

You'r right, that what I understand . Still don't know excactly how it works. ???

Will keep you posted
Greetz
Kropatchek ;D

Title: Re: Cam chain  theory
Post by verslagen1 on 01/10/07 at 22:50:35

It's looks to me that the bolt head "NEDUR" shown on the cover is an access port.  Remove it to get acess to the allen head screw underneath.  Loosen that, adjust the tensioner, then retighten.  Replace bolt, ride.

What I'm concerned with is using a stretched chain for the additional mileage.  What is it going to do to the sprockets?

Title: Re: Cam chain  theory
Post by Savageman on 05/28/16 at 14:22:48

IMHO all types of chains in general are available with different load characteristics. For ex bike chain, motorcycle chain, etc. Well Timing chain shouldn't be any different. If Suzuki would have used the next higher rated timing chain available then all these problems would be a moot point.

Only problem is they used this type (model) of chain so were stuck with using band aids to fix them.

We need to get a roll of Borg Warner Morse timing chain and make our own chains. This is the good stuff.  :o

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