What I must do if I turned GS 850 cam tensioner??

[Guest]

Guys. I am new to the GS 850. I just read that I should not move the auto cam tensioner dial by hand in a document.

I have vague memory of possibly turning it when I first looked at the bike with PO. I had reached under the engine looking for the idle screw and I think I grabbed it and gave a twist before realizing it wasn't the idle screw.

In any case it seemed to me that the cam chain is making excessive noise now. Lots of chain noise.

My question is...is there any way for me to correct the cam chain if I did indeed move the knob? Do I need to do a tensioner reset or something else?

Noob error. Thanks for your help.

[Steve]

If the engine was not running when you turned it, there is no problem.

HOWEVER ... there is always the possibility that it was not installed correctly in the first place. I
t does not take much to verify proper installation, but you will have to remove the carbs to do it.

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[Brendan W]

but you will have to remove the carbs to do it.
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Nuts! What happened to it's tricky but guy ?

[Steve]

Nuts! What happened to it's tricky but guy ?

Huh??

Sorry, but I am only fluent in English (Amurrican).

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[tom203]

I probably check lock screw/lock nut on tensioner and hope that it's currently correct before pondering removal- winter is a good time for carb removal.

[tkent02]

Not so fast.
You can tell if it's working without taking anything apart. Let the engine idle, slowly turn the big knob counterclockwise just a tiny bit while listening to the engine. It will get more top end noise, more rattles. As soon as you hear any change, release the knob. The noise should go away. The fact that the noise comes and then goes away again tells you the tensioner is working correctly. Do not go any farther counterclockwise than it take to effect a slight change in engine noise. Too far and the timing can jump, pistons will hit valves, tons of money will fly out of your wallet.

I have done this on every GS I have ever bought, at least the ones that run, and it has never caused a problem.

If there is no noise increase, most likely someone "adjusted" the tensioner, didn't release the setscrew, and so the tensioner is not tensioning anything. In case you don't know, the stock Suzuki tensioner is fully automatic, there is no adjustment. It should be left alone until it starts to leak too much oil, and then rebuilt and installed properly.


You should also check that the cam timing has not been set wrong by someone before you, it is a tooth or two off on a lot of the bikes I buy.

[Steve]

... winter is a good time for carb removal.

ANY time is a good time for carb removal on the larger shafties.

Only takes 5-10 minutes, including putting the bike on the centerstand and removing the tank.

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[Dogma]

ANY time is a good time for carb removal on the larger shafties.

Only takes 5-10 minutes, including putting the bike on the centerstand and removing the tank.

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...Assuming the rubber parts aren't hardened. In which case they need to be replaced anyway.

[tkent02]

...Assuming the rubber parts aren't hardened. In which case they need to be replaced anyway.

In which case it takes 7 - 12 minutes. A ratcheting tie down will smash the carbs into any old hardened boots.

But yeah, they should be replaced.

[JTGS850GL]

Ya, carb removal on an 850 is all of a 15 minute job.

[Gary_t200]

So if I do your test, turn CCW slightly and release, and if noise doesnt go away then maybe it was left locked out by the lock nut and I need to STOP engine and then release locknut? After releasing nut do I retighten or just leave it loose?

[tom203]

As you turn knob slightly CCW, the noise should slightly change (less pressure on camchain)- if noise stays same your tensioner might have been installed wrong or is frozen. The lock screw is supposed to be backed off tensioner's plunger shaft about one quarter turn and then held there by lock nut so plunger can move out to take up chain slop. Many times people forget to "release" the lock screw after reinstalling.

Edit; see steps 1 and 2 in this link for more explanation....http://www.bwringer.com/gs/camchaintens.html

[subforry]

I just replaced the seals in mine. I did a stupid thing, I was under the impression that I could remove tensioner with the carbs in place. I spent 20 mins removing the bolts only to discover that I had to remove the tank, air box, and carbs, which took less than 5 mins.

[bwringer]

Out of all the cam chain tensioners I've encountered in the wild, about half have had the setscrew tightened all the way by some monkey-fingered doofus instead of left half a turn loose.

If the setscrew is tight, the shaft can't move and the tensioner can't adjust automatically. It has to be left half a turn loose, then locked into place with the locknut so that the shaft is free to move.

So this could be what's wrong with your bike.

Or perhaps it just needs to have the carbs synchronized -- an engine that's running unevenly will be much noisier than usual.

Or perhaps you just aren't used to the normal racket from a GS engine -- it can be pretty startling if you're used to modern bikes.

[Steve]

If the setscrew is tight, the shaft can't move and the tensioner can't adjust automatically. It has to be left half a turn loose, then locked into place with the locknut so that the shaft is free to move.

And PLEASE do not assume the old drag racer's philosophy: "If some is good, more is better!"

i have tested a few tensioners and found that most of them will completely disengage that shaft after about 3/4 turn. If something were to happen with it that loose, there would be nothing to prevent that shaft from coming out and joining the other moving parts inside the engine.

On the other hand, by the time things were loose enough to allow the shaft to come completely out, the timing chain would be broken (to allow enough slack), meaning that valves would already be bent, possibly camshafts broken or pistons damaged.
Yep, a loose tensioner setscrew would be the least of your problems.

As mentioned in step #13 of the tutorial that tom203 mentioned in post #12 (and in the service manuals), that setscrew only needs to be loosened 1/4 to 1/2 turn, then locked into that position with the locknut.

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