Knocking sounds from engine

[haggis905]

I am about to tear down the engine on my 1979 GS1000 that has 143K miles on it. I fired it up for the first time this afternoon (see 'A Wes Cooley in the barn' post today) and ran into some trouble.

Check this link

http://s277.photobucket.com/albums/kk63/haggis905/?action=view&current=DSCN6233.flv

to hear what I heard. Any ideas what I should be looking at? I don't want to just tear in without having some direction.

FYI - its kinda hard to hear on the video

TIA

 

[Steve]

Since the bike is new to you, start with some of the basics, first.

Take off the valve cover, check valve clearances.
Check the spark plugs while you have them out to check the valves.
Verify the cam chain tensioner is working properly.
Clean the carbs and do a proper sync.

You may find that there is really not much wrong.

.

 

[haggis905]

Thanks Steve. I already rebuilt and synced the carbs, but have not done the other things yet. It sounds like the crankshaft is banging around inside the engine casing, however I have not gotten that far yet. I am about to go out and start checking things.

 

[81gs1100]

Really hard to hear in the video, but like it has been mentioned, it might not be that much to it. Cam chains can give you a heart-stopping knock at times to where you think you rolled a bearing or two, only to find the tensioner let loose.

Do you know how, and have you checked the tensioner/tension?

I assume you have already drained that nasty old oil and replaced with a good 10w-40?

Are you holding in the clutch while it started and runs, or did you by-pass the clutch switch and the bike is running with the clutch lever out..? When I first started my 81 GS1100 I had a rag wrapped up holding my clutch in untill I got it running and starting good. Then I removed the rag, started the bike and let out the clutch and I thought I was going to have to dodge shrapnal, it sounded like a dozen bolts being thrown around in the case, pulled in the clutch and it went away, let it out and it started back up. I still have to go in the clutch this weekend and look to see if the basket is loose causing more of this sound thats driving me nuts.

 

[81gs1100]

Ewwww the smoke out the carb issue I totally didn't see the first time reading...

Hmmmm... That sounds to be 1/3 cup valve timing mixxed with 2/3 cup oil coated pistons from sitting for a long long time.

The only way it could push air back out the carbs is the intake valve no being closed before compression has started, even for a tiny bit, like a tablespoon. Or if the intake valve was open during combustion, but then I think you would get some crazy backfiring.

Yeah Im using cooking terms.. I just made some friggin brownies leave me alone, whats a single guy gonna do!!!

 

[Steve]

Another sound that is not particularly friendly is 'cam walk'. Definitely sounds like something is ready to let loose, but does not usually show up (at least in my bikes) until the engine is warmed up for a couple of minutes. That sound is a brief knocking that goes away for a few seconds, then comes back, following about a 5-second cycle. It goes away when the engine is revved up over 1500 or so rpm.

.

 

[81gs1100]

Another sound that is not particularly friendly is 'cam walk'. Definitely sounds like something is ready to let loose, but does not usually show up (at least in my bikes) until the engine is warmed up for a couple of minutes. That sound is a brief knocking that goes away for a few seconds, then comes back, following about a 5-second cycle. It goes away when the engine is revved up over 1500 or so rpm.

.

DOn't even say things like that!! I don't want my bike getting ideas.. :O

 

[Spyderman]

I am about to tear down the engine on my 1979 GS1000 that has 143K miles on it. I fired it up for the first time this afternoon (see 'A Wes Cooley in the barn' post today) and ran into some trouble.

Check this link

http://s277.photobucket.com/albums/kk63/haggis905/?action=view&current=DSCN6233.flv

to hear what I heard. Any ideas what I should be looking at? I don't want to just tear in without having some direction.

FYI - its kinda hard to hear on the video

TIA

if i heard that right and i'm fairly sure i did
that is from the clutch basket rattling
does it go away if you up the idle to about 1500 rpm
if so then it's the clutch basket and not too worrisome you will need to pull it and have the springs replaced and new rivets welded in to it then put it back in and away you go

 

[haggis905]

Steve,

I did run the bike for more than 20 to 30 seconds because of that sound I heard and didn't want to do any (more?) damage. One thing I remembered after thinking about it; the sound went away when it was running at a higher rpm (I didn't have the tach hooked up) but when I dropped it to idle, instant knocking. I will try to get better video with a regular camcorder, but not sure it will be any better.


81gs1100,

I checked the tensioner and there is some hacked up replacement in there that looks like this:

Notice the lovely red goop around where a gasket should be? I found that the intake boots were covered in it.

I also pulled the valve cover and found that one of the inner bolts was snapped off but haven't dug any farther than that. The bike was in neutral when I started it, but I can try pulling on the clutch and see if there is a difference.


Spyderman,

You the second on the clutch theory, so I am going to take a look at it sometime tomorrow.

 

[Steve]

DOn't even say things like that!! I don't want my bike getting ideas.. :O

It's not as bad as it might seem. It's only noticeable at idle speeds. At higher speeds (over 1500), the tension of the cam chain pulls the cams back to the center and you don't hear anything. Somebody on the forum had a fix for this 'problem', but it involved a bit of machining that most of us probably don't have access to.

My wife's 850 has had the cam walk noise since we got it about 5 years ago, and I have not noticed any degredation in performance since then.
#1 son had a 650 for several years that also had the noise. No problems noted there, either.
Have not noticed it on #2 son's 850 yet, and my 850 has not run yet, so I don't know if it's noisy or quiet.

.

 

[tkent02]

First try adjusting that tensioner, a loose cam chain can make ungodly cantankerous noises.

I have score a few nearly free bikes due to this. Sounds like a bucket of rocks got tossed in there.

Clutch rattles can be fairly loud too, but they are easy to diagnose.

 

[Spyderman]

Steve,

I did run the bike for more than 20 to 30 seconds because of that sound I heard and didn't want to do any (more?) damage. One thing I remembered after thinking about it; the sound went away when it was running at a higher rpm (I didn't have the tach hooked up) but when I dropped it to idle, instant knocking. I will try to get better video with a regular camcorder, but not sure it will be any better.


81gs1100,

I checked the tensioner and there is some hacked up replacement in there that looks like this:

Notice the lovely red goop around where a gasket should be? I found that the intake boots were covered in it.

I also pulled the valve cover and found that one of the inner bolts was snapped off but haven't dug any farther than that. The bike was in neutral when I started it, but I can try pulling on the clutch and see if there is a difference.


Spyderman,

You the second on the clutch theory, so I am going to take a look at it sometime tomorrow.

my 1000 just started doing it about 2 weeks ago so i'll be getting my basket done this spring that is kinda how i am just about completely positive that this is what you are hearing
about your tensioner that is a manuel tensioner and needs to be adjusted regularly or you could just put the original self adjusting one back on but that is up to you they made the manuel on for racing purposes

 

[Steve]

THAT is scary.

I know there are several on the board that prefer a manual tensioner, but that one is really scary.
I would suggest a new tensioner, either manual or automatic (stock).

.

 

[haggis905]

I was thinking the same thing Steve. I am all for modifications, but ones that look like they stopped at the local hardware store for parts, um....no.

 

[tkent02]

I was thinking the same thing Steve. I am all for modifications, but ones that look like they stopped at the local hardware store for parts, um....no.

But it should work if it is adjusted correctly. I pull them out and use a pencil pushed in the hole eraser end first to see if the cam chain is making all the noise. Push just the right amount, if there is a certain amount of push where the noise all goes away, I know it is the tensioner.

*Disclaimer* This technique is not recommended for use by others, if you forget to push, the chain skips a few tooth, very expensive bad things happen.

 

[haggis905]

Tom,

This may sound like a stupid question, but you do that when the bike is NOT running, correct?

But it should work if it is adjusted correctly. I pull them out and use a pencil pushed in the hole eraser end first to see if the cam chain is making all the noise. Push just the right amount, if there is a certain amount of push where the noise all goes away, I know it is the tensioner.

*Disclaimer* This technique is not recommended for use by others, if you forget to push, the chain skips a few tooth, very expensive bad things happen.

 

[tkent02]

Tom,

This may sound like a stupid question, but you do that when the bike is NOT running, correct?

No, I do it while it's idling. Might need a helper to hit the starter, if you still have the silly clutch switch hooked up... You have to push the tensioner shoe in the whole time the engine is turning or the chain will skip...

But really that is unnecessary, you have a tensioner in place. Much safer. Loosen the locknut, let the engine idle, turn the bolt in. I like to use a stethoscope to set the manual tensioners, but really just to see if your major noise goes away it is not needed. Just turn the screw in and listen.

It seems very likely this is your noise, if one owner put on that manual tensioner, and the next guy didn't know about it, it WILL be making noise in ten or twenty thousand miles. LOUD NOISE! These chains and guides do wear, that's why the automatic tensioners were invented..

That tensioner looks fine to me, a threaded plate bolted to the cylinder, just like the expensive modern ones. The only thing they have that's better is blue or green anodization.

It just needs an adjustment every year or so, when ever you check the valve clearances would probably do.

 

[haggis905]

So I tightened the tensioner some then fired the bike up again. The sound was worse than it was before, so, running @ 1K rpm, I pulled in the clutch and the sound goes away completely. Release it and its back. Looks like I am pulling the clutch to see whats going on.

my 1000 just started doing it about 2 weeks ago so i'll be getting my basket done this spring that is kinda how i am just about completely positive that this is what you are hearing

Spyderman,

Should I be looking for a machine shop to have the new rivets welded in? I have never been down this road before.

if i heard that right and i'm fairly sure i did
that is from the clutch basket rattling does it go away if you up the idle to about 1500 rpm if so then it's the clutch basket and not too worrisome you will need to pull it and have the springs replaced and new rivets welded in to it then put it back in and away you go

 

[tkent02]

So I tightened the tensioner some then fired the bike up again. The sound was worse than it was before, so, running @ 1K rpm, I pulled in the clutch and the sound goes away completely. Release it and its back. Looks like I am pulling the clutch to see whats going on.

So a clutch rattle, good news, it's easy to fix. Hopefully you got an otherwise good engine, then?

Could be the big clutch hub nut is loose, could be the springs in the back of the basket are loose. (they usually are)
The basket can be rebuilt, by pros or DIY, up to you.

I think it's about $300 to have it done.

 

[haggis905]

Thanks Tom. The engine sounds good so I think it is a matter of rebuilding the clutch then working through the carb syncing, etc. I am thinking I am going to see about doing the work myself so that I have a better understanding of the workings of the clutch.

Once I get the oil drained (so much for just replacing it) I will pull the clutch cover and take some pictures.

So a clutch rattle, good news, it's easy to fix. Hopefully you got an otherwise good engine, then?

Could be the big clutch hub nut is loose, could be the springs in the back of the basket are loose. (they usually are)
The basket can be rebuilt, by pros or DIY, up to you.

I think it's about $300 to have it done.