Cam chain tensioner question.

[KEITH KRAUSE]

I have a noise in the motor that I think may be the chain/tensioner.
My plan is to manually adjust the tensioner knob forward a bit to see if the noise goes away. I just want to be sure of something.
Assuming the tensioner is working properly and the noise is something else, after I advance the tensioner knob will it back off to the correct tension when I release it? Seems to me it will but I just want your opinions. I don't want to add to any problem I may have.
My tensioner did stop working many years ago (original) due to the external spring going limp. I back wound it 1 full turn and it worked fine. I may have to do that again if it will allow it or buy a new one. I'm hoping the noise is the chain being too slack.

 

[Guest]

Is this on the 1000? How many miles are on that bad boy?

 

[Nessism]

Turning that knob will shove the plunger out so if that quietens down the noise, it's time to rebuild/replace the tensioner assembly.

 

[KEITH KRAUSE]

Is this on the 1000? How many miles are on that bad boy?

It had 106,000 miles back in '99 when I decided to do a complete restoration. Vance and Hines did the engine work. I've got about 34,000 on the rebuilt motor. The rebuild included a new genuine Suzuki cam chain and guides. I doubt the chain is at fault, especially when the original lasted 106K and was still working fine. While doing some other work several years ago I noticed the tensioner spring had lost tension. I don't know if it was applying enough tension when I caught it but I didn't notice any odd noises. I wound it back one turn and it seemed to work fine, advancing through its entire range.
To tell you the truth I'm worried the noise I hear is something else and all I can do is monitor it. I'd at least like to try advancing the tensioner while it's running to see if the noise goes away. I'm pretty sure that you can advance it and the motor will back it off to correct tension as soon as you release the knob but I just want to be sure. If the noise does go away I plan to just get a new tensioner and probably won't try back winding the spring again. Just a new spring would be cool but I doubt you can buy just a spring.

 

[Guest]

Get an APE manual cam chain tensioner.

 

[KEITH KRAUSE]

Turning that knob will shove the plunger out so if that quietens down the noise, it's time to rebuild/replace the tensioner assembly.

Correct. But what I need to know is if you manually advance the tensioner (assuming it's working correctly) will the motor back off the tensioner automatically as soon as the knob is released? I think it does but just wanted opinions.

 

[KEITH KRAUSE]

Get an APE manual cam chain tensioner.

Yeah, yeah, yeah.
What about my question. Surely you've played with these things.

 

[tkent02]

Buy a new spring, this one has earned retirement a long time ago.

 

[Nessism]

Correct. But what I need to know is if you manually advance the tensioner (assuming it's working correctly) will the motor back off the tensioner automatically as soon as the knob is released? I think it does but just wanted opinions.

Yea, the plunger will automatically adjust itself once you release the knob, assuming the tensioner is working properly.

 

[Guest]

With the spring on the knob see if you can wind it tighter one more time around.
There is also a spring that pushes out on the piston but could be deemed useless with dirt and old crusty oil.
Where's Bwringers link?

 

[Nessism]

The rod that holds the knob/spring also has a ball bearing and a ramp on the other end. This ball bearing pushes on the tensioner plunger. After a while the parts wear and the plunger rod does not move smoothly. You can test this by pushing on the plunger with your thumb while winding the rod in both directions. If the parts are in good shape the plunger will move smoothly in relation to twisting the knob. I learned all this by rebuilding a few different tensioners; it took me a while to figure out why some felt smooth and others were rough. If the tensioner has more than 100,000 miles on it, most likely it's time to replace it (but check first to be sure).

 

[bwringer]

To answer the question, you can't tighten the tensioner (increase tension on the guide blade) by twiddling the knob.

However, you can release tension, and taken far enough, you could cause the cam chain to skip a tooth. So, uh, don't do that.

The tensioner is basically a mechanical one-way valve -- it will extend, but it can't go back (unless you remove and reset it).

Here ya go:
http://bwringer.com/gs/camchaintens.html

As Nessism described above, I have also found a couple of tensioners where the ramp at the end of the pushrod had some dents from the ball bearing in the tension screw. This will cause the tensioner to stick at a certain setting.

On my bike, I simply sanded the ramp until it was smooth again and have had no further issues. Or you could just get a new pushrod for $20 - $25.

 

[Nessism]

The tensioner is basically a mechanical one-way valve -- it will extend, but it can't go back (unless you remove and reset it).

Ya know...I wrote a response earlier today about how the pushrod will extend but not go back since this seems like the proper way for the tensioner to work, but I pulled out a spare tensioner just to double check and the plunger on this thing will go both in and out when turning the knob. Maybe its fubared up but that's how it works. The hot rod guys will tell you about how the tensioner will go back in under tension thus the need for a mechanical device to eliminate this concern. I believe it now.

 

[Dogma]

Ya know...I wrote a response earlier today about how the pushrod will extend but not go back since this seems like the proper way for the tensioner to work, but I pulled out a spare tensioner just to double check and the plunger on this thing will go both in and out when turning the knob. Maybe its fubared up but that's how it works. The hot rod guys will tell you about how the tensioner will go back in under tension thus the need for a mechanical device to eliminate this concern. I believe it now.

Interesting reading. I was just checking the function of mine before I put it back on last week. It would only back up if I backed the knob off. ...And now that it's properly lubed with moly paste, it comes back out smoothly.

 

[Guest]

The tensioner is basically a mechanical one-way valve -- it will extend, but it can't go back (unless you remove and reset it).

As Nessism described above, I have also found a couple of tensioners where the ramp at the end of the pushrod had some dents from the ball bearing in the tension screw. This will cause the tensioner to stick at a certain setting.

this is my experience as well.

there is nothing that would pull the pushrod back in (towards the knob)just by rewinding the knob - i.e. while the tensioner is out of the engine.

however, if the tensioner is in the engine and you loosen the knob the chain through its slack is going to push the rod back out.

hopefully, this answers your question?

 

[bwringer]

Sorry, I sort of misstated things -- if you grab the knob and twist counter-clockwise, it will indeed allow the pushrod to retract and loosen cam chain tension, if there's also something (your finger, the cam chain) pushing against the spring.

What I meant was that in normal operation (no large mammals fooling with that lovely, tempting knob), it acts as a "one-way valve" -- it can extend but not retract.

Of course, if the ramp in the end of the pushrod has dents in it, it can indeed get hung up at a certain spot. Keep yer mitts off that knob, and it'll usually be fine.

If you truly desire a manual tensioner for some reason, simply tighten the setscrew all the way.

I have found that on about half of the engines I encounter, someone has mistakenly locked the pushrod -- instead of leaving the setscrew half a turn out so the pushrod can extend when needed, they've tightened the setscrew all the way. Eventually the cam chain gets a little slappy, since there's nothing compensating for wear.

On a street engine, there's absolutely no need for a manual tensioner unless you just like the way they look or you like sending money to APE.

 

[Don-lo]

Keith, the question seems to be is the tensioner providing enough push to keep the chain tight. I agree it could be the spring, or ramp. Here is how I tested that theory a few years ago. I locked the setscrew before removing the tensioner, then carefully measured the distance the plunger was out. I loosened the setscrew and found that indeed there was not much more extension left. I reset the plunger to the original distance, then added a little more (1mm?) and locked the setscrew. This essentially turns your tensioner into a manual setting. Reinstall but don't release the setscrew. You are adding more tension, but it is distributed over the whole cam chain and any extra will be absorbed by the curved tensioner. It is taking a chance, but I am sure that some people with manual tensioners overtighten cam chains more than this all the time. Anyways, it did quiet the chain noise down a little, and I drove it for a few years like that, then got a new cam chain.

 

[doctorgonzo]

Get an APE manual cam chain tensioner.

Once you go manual you never go back.

 

[Guest]

On a street engine, there's absolutely no need for a manual tensioner unless you just like the way they look or you like sending money to APE.

i'll second this

but ape tensioners do look cool

 

[Guest]

Oh I just fiddle with my APE cam chain tensioner too much. I can't keep my hands off of it.