850 Engine Noise

[93Bandit]

Hey guys. I've noticed a lower end engine clatter type noise on my 83 850. It only happens once it's fully warmed up and usually only after a decent ride. I can only hear it at idle. To me, it almost sounds like maybe transmission noise? It goes *clatter clatter* moment of silence, then the noise again. It's not a constant knocking. No difference with the clutch in our out. I've only noticed it when idling in neutral, haven't noticed it when in gear and the clutch is disengaged.

Is anyone familiar with what I'm trying to describe? I'm not sure if it's an issue or just the way it is. Any thoughts are appreciated.

 

[Steve]

Probably not in the lower end. More likely at the top of the engine. What you have described is the classic sound of "cam walk". The thrust surfaces that keep the cam from 'walking' from side to side have worn a bit, and the cam makes a bit of noise as it bangs from side to side. As the engine speeds up a bit, usually above about 1500 RPM, the tension of the cam chain keeps the cam centered, so it does not tend to hit either side.

There have been methods proposed (and done) to repair this, but unless you are an accomplished machinist, or are willing to pay one, it's best to simply ignore the sound and accept it as part of the experience.

My wife's bike had that noise when we got it with about 44,000 miles on it. It is now approaching 70,000 miles, still makes the same sound. Has not gotten any better, of course, but hasn't gotten any worse, either.

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[93Bandit]

Ah yes, I've read about that but I'd forgotten about it. If it's not detrimental to engine life, I'm not going to worry about it. Thanks Steve.

 

[steve murdoch]

There are a couple clips on Youtube of GS cam walk.
https://www.youtube.com/watch?v=GZtAZZVCpxs

 

[93Bandit]

Yep, that is exactly what it sounds like. I'm going to ride on and not worry about. :encouragement:

 

[93Bandit]

My wife's bike had that noise when we got it with about 44,000 miles on it. It is now approaching 70,000 miles, still makes the same sound. Has not gotten any better, of course, but hasn't gotten any worse, either.

.

Off topic, but how does her bike run with that many miles? Have you had to rebuild the engine? Burn any oil? I suspect with your reputation on here that it's been well cared for, so likely runs well. I'm just curious of long term high mileage reliability.

 

[Grimly]

The '79 850 did it from the day I got it to the day I pulled that engine, 120K miles later. The replacement engine sometimes did it, but not that much, and only when in London traffic.
The '80 bike always did it, in the PO's keeping and always did it in mine. The (mid-80s) engine I fitted later rarely did, and in recent years when it has done it, it's been so unusual that I've noticed it right away. I suspect Suzuki may have addressed the issue in the mid-80s.
Pure luck of the draw. It means nothing and harms nothing.

 

[Grimly]

I'm just curious of long term high mileage reliability.

Change the oil every 2K miles and don't thrash it absolutely everywhere and it will outlast you.
Only reason I pulled the '79 engine was the PO had been a clutchless changing moron and had ruined the dogs on 2nd gear. That, and the eventual leakiness and refusal to start one morning because of low compressions caused by overheating the previous day making the rings go soft, made the decision for me.
I still have that engine and might get around to rebuilding it and putting it back into that frame, as the bores and pistons were entirely unworn at 140K.

 

[GS1150Pilot]

I'm glad this post came up. I had asked about a similar sound in my Bandit 1200 and a (wise) member had suggested it might be cam walk. Having adjusted the valves and timing chain (manually with an APE unit), my Bandit still clatters like that, so I'm inclined to think that is what the Bandit is doing as well.

Cool thread.

 

[Guest]

A bike mechanic acquaintance claimed this was due to wear on the tappets, and replacing them would solve some GS low RPM clacking problems? Ive not tried that myself, nor ever seen any proof that is true, but I'm not super knowledgeable so those smarter than me, what say you?

 

[Steve]

Off topic, but how does her bike run with that many miles? Have you had to rebuild the engine? Burn any oil? I suspect with your reputation on here that it's been well cared for, so likely runs well. I'm just curious of long term high mileage reliability.

The engine has been apart for some gaskets, but still has the original rings. Not enough oil burning (or leaking) to worry about. Thanks for the comments about my rep, but there are times that it's like the cobbler, whose kids run around barefoot. Yes, it runs well. I still need to do a permanent repair to the coils, but I would feel VERY confident to change the oil, check the air in the tires and take it cross-country tomorrow. By the way, I was off just a bit on the mileage. Just looked in the garage, the odometer is showing 73,351.

A bike mechanic acquaintance claimed this was due to wear on the tappets, and replacing them would solve some GS low RPM clacking problems? Ive not tried that myself, nor ever seen any proof that is true, but I'm not super knowledgeable so those smarter than me, what say you?

It would take quite a bit to get the hardened tappets (shims) to wear on these bikes, and even if they did, they would still be clicking as the engine sped up a bit. All of the GSes I have heard with cam walk had the noise disappear long before 2000 RPM, when the cam chain was pulling them to the center.

Besides, the clearance between the cams and shims is so small, they don't have enough room to make noise. :-\\\

.

 

[93Bandit]

That's comforting, Steve. I'm relatively new to the bike world and have always heard a generalisation that a bike with 25,xxx+ miles is considered "worn out" so I was a little hesitant to buy mine, which had about 23,000 when I bought it. However I'm finding out that's not really the case as long as they're cared for.

My 81 shows 44k on the odometer, which makes me wonder if I should freshen it up when I have the engine out of the frame. Definitely want to do gaskets since it leaks, but I wonder if I should do a quick cylinder hone and rings and valve seals while it's apart. I also believe in not fixing something if it ain't broke, so...

 

[Steve]

You can certainly wear out an engine in just a few miles, but the Suzuki GS engine was a bit over-built and many of them have gone well over 100,000 miles. It is a bit unfortunate that a couple of the gaskets that are prone to leakage require a rather extensive dismantling of the engine, but the internal parts are certainly up to the task.

At 44k, if the gaskets are not leaking, I would not worry about the rings. However, if you are taking it apart to change gaskets, the rings are one of those "while you are in there ..." items. New OEM rings are not cheap. Many of us are using rings from Cruzin Image and have had good results.

Since you have to go through all the same effort and gaskets to do the valve seals, it only makes sense to do them, too.

.

 

[93Bandit]

You can certainly wear out an engine in just a few miles, but the Suzuki GS engine was a bit over-built and many of them have gone well over 100,000 miles. It is a bit unfortunate that a couple of the gaskets that are prone to leakage require a rather extensive dismantling of the engine, but the internal parts are certainly up to the task.

At 44k, if the gaskets are not leaking, I would not worry about the rings. However, if you are taking it apart to change gaskets, the rings are one of those "while you are in there ..." items. New OEM rings are not cheap. Many of us are using rings from Cruzin Image and have had good results.

Since you have to go through all the same effort and gaskets to do the valve seals, it only makes sense to do them, too.

.

That's exactly my thought process as well. I haven't heard the 81 run, so I have no idea what the condition is. I'd hate to tear it all down for gaskets and then discover once it's back together that it burns oil and have to tear it down again. I've done lots if engine work on cars/trucks and usually replace other parts while I'm inside for the same reason. Nothing sucks more than just doing the minimum and to save a few bucks when I should have spent the extra money to save time and headaches later on.

 

[wymple]

I got my 850 with 32K on it. It's around 70K now, and has always sounded like that.

 

[Steve]

I'd hate to tear it all down for gaskets and then discover once it's back together that it burns oil and have to tear it down again.

Where motorcycle engines differ from car engines is in the way they are designed. Yes, the valves are still in the head and there are seals around the valve stems, but when you remove the head on a bike engine, you will disturb the gasket at the base of the cylinders, requiring pulling the cylinders off the pistons to change it. Pulling the head on a car engine is comparatively easy. That is why we tend to do some preventive stuff "while we are in there". :encouragement:

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[Gorminrider]

Is it just the "shim" bikes that exhibit cam-walk? and is it just the 4 cylinder bikes?

My screw-adjust tappets on GSX twins do not do this. I wonder: do the GSX 4s?
It's too bad...re-selling a bike that is "glock-glock glocking" at the top end is not so easy...buying one without fore-knowledge is discomfiting.

 

[Steve]

Is it just the "shim" bikes that exhibit cam-walk? and is it just the 4 cylinder bikes?

Good question. :encouragement:

I wish I had a good answer for it.

I don't do much work on twins, also don't do much on "non-shim" bikes, so I have not noticed whether they have cam walk or not.

.

 

[Guest]

Is it just the "shim" bikes that exhibit cam-walk? and is it just the 4 cylinder bikes?

My screw-adjust tappets on GSX twins do not do this. I wonder: do the GSX 4s?
It's too bad...re-selling a bike that is "glock-glock glocking" at the top end is not so easy...buying one without fore-knowledge is discomfiting.

I replaced all the shims on my 450 with new OEM gs500 ones which appear to be some sort of sintered metal [??] and the cam walk racket went away and has never come back. I'm suspecting that a shim which isn't dead square or maybe worn concave could induce cam walking. Given that the shims were readily available and cheap.....that said, GS500s were known for cam walk and various measures were tried by Suzuki such as a sprung endplay shim to cure it. It seems as though either having so little endplay that the cam can't get a run at its destination or so much that it changes its mind before it gets there can relieve it.

The head expands way faster than the cam, so achieving a constant endplay is impossible. The beauty of bucket followers is that they rotate and present a constantly changing face which avoids the grooving and galling that can plague lever type followers. However, in order for them to rotate, the cam lobe is slightly off center which induces a side motion which reverses as the lobe goes over center. The GSX motors shouldn't, in theory, have cam walk.....

 

[Gorminrider]

Ah,so! Between yours and Steve's explanation (post2), I can pretend to have an intelligent handle on it! And I now know it's a feature of the "shim 'n bucket" twins too.