1981 GS850G clacking noise on idle vids..for you to listen not sure what it is?

[Guest]

Just bought this bike.. regretting it kinda? New two the forum, Hi everyone

Anyway its a 81 GS850G only 37,000kms had collector plates, in good shape, brakes decant (maybe use pads) Tires good, shocks good, clutch tranny good, body not bad, reupholstered seat! But this clanking knocking noise is driving e crazy! I was told it needed a timing chain, but it feels tight to me, how do you check? And has anyone had luck with the KL chain, that you can split, so that you don't have to split the case? three of my exhaust valves are under .04mm and one of my intakes are two! All exhaust shims are currently 2.60mm thick, can sneak the intake out easily without the proper tool from motion, but I highly doubt that's what's causing the noise? It certainly doesn't seem like bottom end, or it would get louder with revs, and it almost seems to be half the engine speed? So I'm thinking cam, or cam chain related, but it looks ok?

Is the starter clutch supposed to have side to side play? Not lateral play, free wheels one direction, but I can move in side to side. wiggle it. The starter gear moves in and out, let me know what you think! I'm at a loss as to what it is?

[almarconi]

I agree with your assessment that the noise is coming from the upper part of the engine. I would start by getting a factory service manual. Most manuals have specs for the timing chain, how to measure stretch..etc. You will need to remove the valve cover anyway to repair the oil leak so you may as well adjust the valves. I would carefully inspect the head to make sure it is not cracked. The timing chain tensioner may need to be cleaned or rebuilt, the manual has a procedure. Is the engine oil level correct? 23k miles is nothing for an 8 valve engine, I would adjust the valves, inspect the cam chain and make sure the chain tensioner is working properly, replace the seal on the tach cable, new valve cover gasket..etc.

[04colyZQ8]

I think it's the tappets according to the other guys vid in this thread

http://www.thegsresources.com/_forum/showthread.php?216227-GS750-engine-noise

Good to hear that the 8v engines are good!

[SailEXIT]

Sounds like cam walk to me.
My bike does the same thing.
It has been doing it for a long time.

Found this on BikeCliff's site.

http://members.dslextreme.com/users/storagecliff/images/cam_end_float_mod.pdf

A good read for sure.

Shaun

[2BRacing]

Congratulations, that is a nice-looking bike and it sounds good as well!

I agree that that "tickety-tack" sound is the so-called "cam walk". My bike has also being making that noise for years (has done about 40 000 km now), but it never gets worse and does not affect performance. It goes away at higher revs. You do not have to worry about that noise - just ride! Do not fiddle with the automatic cam chain tensioner, and specifically do not turn it with engine stopped or running.

The oil leak under the front left side cam cover cap is from the rubber half-moon inside. Easy to remove and replace - plenty of threads here on how to do it. You should attend to the valve shims at the same time to get the correct valve clearances.

The oil leak from the tach cable seal is also easy to repair - see this http://bwringer.com/gs/tachcableseals.html

If you have not already found this useful cache of information, go here http://members.dslextreme.com/users/bikecliff/ You will find answers to all your questions, and much more!

[Chris G]

No expert, but when I heard the noise first thing I thought was cam walk, my 850 does it comes and goes never bothered me even before I found out it's quite common, good time to check the clearances sort the leak, general all round coat of looking at and ride that baby.

[04colyZQ8]

No expert, but when I heard the noise first thing I thought was cam walk, my 850 does it comes and goes never bothered me even before I found out it's quite common, good time to check the clearances sort the leak, general all round coat of looking at and ride that baby.

Thanks 3 exhausts are tight, and one intakes border line tight. Currently sitting with valve cover loose, side over gaskets been disturbed (checking the starter clutch, does it look ok, in the vid should it be loose like it is?

Congratulations, that is a nice-looking bike and it sounds good as well!

I agree that that "tickety-tack" sound is the so-called "cam walk". My bike has also being making that noise for years (has done about 40 000 km now), but it never gets worse and does not affect performance. It goes away at higher revs. You do not have to worry about that noise - just ride! Do not fiddle with the automatic cam chain tensioner, and specifically do not turn it with engine stopped or running.

The oil leak under the front left side cam cover cap is from the rubber half-moon inside. Easy to remove and replace - plenty of threads here on how to do it. You should attend to the valve shims at the same time to get the correct valve clearances.

The oil leak from the tach cable seal is also easy to repair - see this http://bwringer.com/gs/tachcableseals.html

If you have not already found this useful cache of information, go here http://members.dslextreme.com/users/bikecliff/ You will find answers to all your questions, and much more!

Thanks! Great I'll check those threads, might have to order parts and wait, or silicone it for now. Cam walk to eh?

Sounds like cam walk to me.
My bike does the same thing.
It has been doing it for a long time.

Found this on BikeCliff's site.

http://members.dslextreme.com/users/storagecliff/images/cam_end_float_mod.pdf

A good read for sure.

Shaun

Yeah I found that the other night, I know a competent machinist, who would likely work for cash or beer, and could easily make the half moon side shim. Just its a lot of work, requires removing the head, just want to be sure its not the tappets, as a guy in another thread with a GS1100 found, I have a feeling that its the problem on mine, as is clack sounds exactly the same!

I'm wondering if the tappets are loose and rotating, and you have cam walk, it will accentuate the rotating? Perhaps replacing the tappets lessons or wards it off for now, perhaps its a compound issue? supposedly early 850s tappets were machined incorrectly, to small, and make the noise.

You can do a Lean test while running, should quite up? How far to lean, the bike over, and to which side?

I agree with your assessment that the noise is coming from the upper part of the engine. I would start by getting a factory service manual. Most manuals have specs for the timing chain, how to measure stretch..etc. You will need to remove the valve cover anyway to repair the oil leak so you may as well adjust the valves. I would carefully inspect the head to make sure it is not cracked. The timing chain tensioner may need to be cleaned or rebuilt, the manual has a procedure. Is the engine oil level correct? 23k miles is nothing for an 8 valve engine, I would adjust the valves, inspect the cam chain and make sure the chain tensioner is working properly, replace the seal on the tach cable, new valve cover gasket..etc.

I have a Clymer's manual, and original owners manual were do you get the factory one from?

[2BRacing]

I have a Clymer's manual, and original owners manual were do you get the factory one from?

In BassCliff's treasure trove of information: http://www.mtsac.edu/~cliff/storage/...nual_HiRes.pdf

[SailEXIT]

Here is a video of what my bike sounds like.

Shaun

https://youtu.be/wBAckwkiWi4

[wymple]

Sounds like cam walk to me. Mine does it, not quite that prominent, and has for 2 years. Goes away right off idle.

[04colyZQ8]

Fixed!!! It was the cam buckets, replaced 7 tappets with NOS ones from my local dealer (modern motorcycle in Vancouver) they actually had them in stock, for 10.00each!! I bought some shims, and gaskets, oil for a total of 289.00. I tore off the intake, carbs, tank, cycler 3 intake boot, chain tensioner, right crash bar, ignition/timing cover, ignition pickup, horns, plug wires, breather, valve cover, chain idler, both cams, and then final the buckets. The buckets are tough to remove, and was told not to use a magnet, otherwise you could cause metal fillings to stick to the parts. I use a flat screw driver to lift up on the shim, and used oil tension, to lift up the tappet enough to grip it with my fingers a pull it out, this was tough and I had to try several times on each one. Upon inspection all of the exhaust tappets showed signs of burnt oil, and ware around the tops and bottom, from spinning in its bore. The worst intake tappets were the right most one (from running dry? highest point when on the side stand (lack of oil) I only had 7 tappets, so I reused the best looking intake bucket from the oil soaked side. I then installed the cams, and shimmed the valves, using a small screw driver to depress the outer buckets, as I didn't have a special tool! The inner ones I loosened the cam bearing caps enough to slide out, and in shims. I spent a lot of time shimming. I wound up with:

all 4 intakes 0.06mm and all 4 exhaust 0.08mm which is little high, but they will were closer. Spec is 0.03mm-0.08mm

I had to make a gasket for the valve cover as they gave me a 550? gasket?? Anyway I used gasket material and it seems leak free so far.

I was 180* out of time and it wouldn't start, had no compression, Clymer is not clear about placing the #1, and #4 pistons at TDC, before lining up the marks. So beware, don't make my mistake, had to tear it all apart again, and retime it! Ounce I did that it started right away! If you unsure you can bump the starter with the valve cover and carbs still of, with a compression tester to verify its not 180* out.

Anyway the bike sounds great no noise! just a intermittent tick, that has since gone away, might have been a sticky link in the timing chain, or a plug wire grounding out on the Horn?

If yours sounds like my first video I highly recommend installing new tappets!

BTW, my cam end play was 0.15mm intake, and around 0.2?mm on the exhaust, and no noise!

I have a theory, what causes cam walk, and bucket wear! running the bike on the side stand for extended periods of time, or revving it out, isn't good, the two top right tappets are running almost dry, the only way that I see they get oil is from the chain, splashing it around, and it drains out to quick when on a angle, on the stand, and the thrust surface on the left exhaust cam, had the most amount of wear, likely due to sitting on the side stand, for extended periods of time while running, the weight of the cam itself will put extra pressure, on the thrust surface, when on a angle!

I know refuse to run the bike on the side stand, unless someone can convince me otherwise, I'll let it run for one minute on idle, then stand it up.

Few pics, and lastly a video proving its not quite! Thanks for all your hep so far guys! Still need to fix cable seal, and I badly need knew intake boots, from intake to carbs.

[04colyZQ8]

More pics, wont let me post more then 10 pics per post?? Hopefully they are in order now?








and vid

[Dogma]

Nice work. Beautiful bike.

I've never heard of that problem before. The only buckets I've ever heard of being damaged on an 8 valve GS (8 years here on the forum) were a bike that was left idling for half an hour. They were blue when we took it apart.

Lubrication design on these is fine. They are lubed from the copious oil pumping out of the cam bearings. (Journal bearings do that.) The valve train is normally bulletproof except for lack of adjustment or running the bike without oil, letting it overheat, or some other neglect. The 850 loves to rev; it's not a problem. 5 or 6000 rpm to redline is where the 850's "second" engine wakes up. Don't fear for its safety there.

[steve murdoch]

Good work on getting rid of the top end racket.
I would get a big fan to blow air on the engine while you are working on it.

[04colyZQ8]

Good work on getting rid of the top end racket.
I would get a big fan to blow air on the engine while you are working on it.

Yeah? What about In traffic you'd be sitting there just the same?