Manually replacing ACCT springs - Kawasaki Vulcan 750 Forum : Kawasaki VN750 Forums
 
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post #1 of 1 (permalink) Old 01-15-2006, 11:51 AM Thread Starter
Vulcan Verses
 
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Manually replacing ACCT springs

Quote:
Q: I have been following this thread and wondering, other than sound, how would I know if my Cam Chain Tensioner Spring needs replacing? Is there any way to tell other than the sound? Unfortunately, I don't have ready access to a benchmark to compare the sound to and don't really know if my bike sounds normal or has too much "clappity clap" going on. I haven't really noticed any but then again I really have no point of reference. Also, Clymer's (p. 178) indicates that inspection of the assembly includes ensuring that the ratchet operates properly. This is confusing to me as I thought I remember other posts on this topic indicating that there really is no adjustment because when you turn the screw to adjust it, it just returns to it's original position but "inspecting the ratchet operation" to me implies that there should be some adjustment capability. My bike has a little over 6200 miles. Should I be concerned?
A: Hi Cory: It is not a terribly difficult job to replace them yourself - but it does require a bit of dexterity. I am in the process of posting pictures and directions on my website.

The springs are located on the inside of the Automatic Cam Chain Tensioner, which is located on the rear of each of the cylinders.

Removing it from the bike is easy - 2 10mm bolts. For the rear cylinder you need to remove the coolant overflow tank, which is also a 10mm bolt. The springs are $10.00 each plus $2.25 per order for shipping. My bike was making a "clack, clack, clack" and that was the cause of the noise - and I understand that this is a common issue. Like I said below, I didn't recognize the sound of the bike once I changed them out. As far as the manufacturer - I had them made for a group of us here on the list from a spring manufacturer in Ohio, but I ordered a bunch extra in case others needed them.

These are better than OEM in that if you want OEM springs you need to spend ~$80 to replace the entire ACCT. These springs are $10, although you need to rebuild them yourself (or send them to me and I'll do it for $25.00) Some pics and a brief description on how to rebuild are on my website. http://www.tocmanufacturing.com/new_page_6.htm Take a look and let me know what you think! Main point is, Kaw wont sell just the springs - they will only sell the entire ACCT assembly.


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Okay... Where can I get a set of beefy springs?

My experience has been that when you hear the cam chains slapping 1 of 2 things have happened:

1) the spring has broken and you get a very distinctive, hard, slapping noise

or

2) the spring has "slipped" and needs to be re tensioned.

What I mean by slipped is that there is a groove in the tensioner that a leg of the spring rests in to counter the twist that the spring is being used to provide in other words, to fix one end of the spring while the other is tensioned. Sometimes the spring slips out of the groove and loses the ability to keep tension on the chain guide. I have not yet experienced that all elusive 3rd option, where the chain has stretched so much that the tensioner is at it's limit of travel. When that happens, I have heard rumors that in Canada you can buy an extender that gives the tensioner about 1/4" more length. I'll be exploring that option after replacing the spring no longer works. I really hate pulling the motor. The Replacement spring is just to help resolve problems number 1 & 2. Hope that helps. As far as gaskets there is no gasket to replace when removing / installing the tensioner.

The spring replacement is not "easy" in the sense it takes a bit of manual dexterity or a partner to replace or re tension it. After doing it 3 or 4 times, it can be done in about 10 min, although the first time I tried it took me 45 min and the assistance of a partner. I will publish some detailed instructions, so the process will be straight forward, but even though the instructions may be clear, it still takes a bit of practice and some skill and luck. that said, I think that most folks on the list who can effectively turn a wrench should be able to do the replacement especially if it is a necessity. While at ES, I had one of my springs fail, and I was able to re tension it in about 15 min with the tools I had with me a 10mm deep socket, and a curved pick. Regards James M Larson


The stouter wire diameter of the tensioner spring is a good idea, but there are two things to be wary of:

1) there is *very little* clearance between the adjuster screw and the inner wall of the tensioner body, and this spring manufacturer NEEDS to be aware of the tensioner design and limitations for this space. They can duplicate the spring, surely, but will it fit? They will need to have a donor tensioner to understand. Truth be known, it'd be nice if Kawasaki would design a larger tensioner body to accomodate a larger diameter spring, but it probably won't happen.

2) *too much* spring tension is just about as bad as not enough. I mean, when it comes to disassembly and reassembly, you have to be a bit savvy on just how much to wind the new spring so as to not create a heavier load against the chain guides, lest you prematurely wear the teflon surface the chain rides on. In addition, too much tensioner pressure can stretch the timing chain over time, wearing the link pins. This exascerbates the loose timing and very heavy load can actually cause the chain to fail over a long period of time not good!

Before disassembly, best to get a feel for *how much* spring pressure the stock tensioner has upon removal from the engine, wind it up and let it snap into the extended position. This will give you some idea of how much spring tension it has, and a close duplication with a stouter, longer lasting spring (or close) will be ok. ON THE OTHER HAND, I got sick and tired of tensioner problems eating up my cam gear sprockets and devised a tensioner modification this past summer beleive it or not, doing away with the spring altogether! I plan on posting an update and explanation of how I did it on my website in January. I very recently did a teardown to refresh my heads and examined any wear problems using this modification and found none after running 31,000 miles this past summer! Wish I could chime in here more frequently. I don't have a newsreader and find having to sign in, website board, etc time consuming. Course, anyone can email me directly anytime.

My website, for anyone that hasn't seen it: http://ourworld.cs.com/Moonmist115/vulcanwebsite.html

Stay tuned! Maybe I can make springs a thing of the past! I'm in the process of getting blessings to go ahead from Kawasaki to patent my idea not sure how long that will take. gYpSy

Quote:
gYpSy: you are correct there is not much clearance. the original spring is .026" diameter, and I was thinking of going to to about .028 .029" so I don't think the increase will create a clearance issue.

As far as the increase in spring tension by using a beefier spring, my thought is that the original spring is probably pre loaded about 1 turn, and there are about 3 more turns needed for full compression. with a new set of chains, the spring remains compressed by about 4 turns. after enough wear to fatigue the spring to failure, the tensioner in my bike as extended about 2 turns. the conclusion I drew from this is that with a beefier spring, and a 1 turn preload, there will be only about 2 more turns needed to compensate for the stretch in the cam chain, so the replacement spring will only be loaded about 1/2 as much as a would be required with a new set of cam chains. I'll definitely check out your website, as this whole tensioner issue is a pain in the butt so eliminating it would be a much needed improvement. thanks for the feedback. Regards
James M Larson
Quote:
The cost for the spring is the same if we use .026" or .028"wire, so I figure if we go through any trouble at all which I plan on doing as I am to cheap to spend 140 bucks to replace the original tensioners with new since I believe they can be rebuilt (despite what Kaw is saying) we might as well see if we cant get a bit more piece of mind. I don't think that they will last longer than the originals 90,000,000 cycles (see my other post for the calc) is a good number of cycles for either spring to last original or replacement, I just would like to do this as an $10 $20 option to replacing the entire unit.
Regards James M Larson
Thanks to GC and Grambo for the help they gave me getting my ACCT problem figured out. I reloaded the spring last night according to Gypsy's website but the true test came this morning when I started up the bike when it was cold and I found the noise was gone. Boy am I a happy camper now that my bike is runniing smooth again. I had to get out and ride so the wife and I rode to breakfest. "Live to ride, ride to eat". Putting the tensioner back together does take about 4 hands to get it done. I guess I got lucky and got it done on the first try. I put the tensioner body in a cloth and secured it on my vise, snugly. I had my wife hold down the collar with a small flat scewdriver as I loaded the spring with one hand and put the rest back together with the other.

Last edited by Vulcan Verses; 01-15-2006 at 11:56 AM.
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