Dreaded ticking/tapping noise

[wheetbix]

I was riding one night for quite some time, emptied the tank and decided to top it up. No problems for about 2.5 hours total of riding that night. The next day I was riding in to work when I suddenly felt like I had lost power, which then led me to notice what sounded like my tools rattling around (my tool pouch had fallen apart so I had been keeping my tools in my carry case).

I decided it's best to pull over, to which I then realised my precious 2009 Suzuki GS500F was making that noise!

After towing it home I decided to catch this video snippet, I don't want to run it any longer than necessary.



Things I've done:

1. Checked the automatic cam chain tensioner - I took this out, ensured it did not unwind by pressing on it, wound it all the way up and reinstalled ensuring it clicked out.

2. Took the cylinder head cover off and checked the camshaft timing marks were not out of sync and stayed in sync for a few rotations of the engine

3. Valve clearances - both intake valves were out of spec (I couldn't fit my 0.03mm gauge in either of them) - I fitted the next size and they are within spec now.

4. Before turning the engine over I pulled the spark plugs out to make things easier. I noticed both plug tips were white (must be running lean, makes sense due to the valve clearances I found)

5. Renewed spark plugs, engine oil and oil filter

6. Since I was already there, and the schedule asked nicely, I tightened the head bolts and replaced the copper washers and applied RTV to the gasket before reinstalling the head cover.


All of the above and the sound persists... I have noticed when the engine is cold it doesn't make the sound as much, it's quiet then comes, then quiet again. Once it warms up it's just constantly there.

I have uploaded the video to YouTube so you can have a listen. I would really prefer to find out the root cause of this.

[DarkCyDE]

kinda sounds like rod knock. Id wait for one of the pros to chime in, but it sound like bearings or a stretched rod.

Mike

[wheetbix]

Hmm, I am hoping that's not case. I just spent ages repainting the bike

[DarkCyDE]

I hate to say, I two, have had that happen back in my twenties. Who knows, one of the more enlighten, may have a better answer.

[wheetbix]

I decided to fire her up again and use my 3 extention adapters with a screwdriver on the end to really get around and have a listen.

Because when it's cold the sound comes and goes I felt like time was of the essence. As I listened around I waited for the tick to come then disappear before moving around.

I could actually feel the entire mechanics stethoscope send shockwaves as the ticking appeared then settle when the noise disappeared when the steth was touching the cam chain tensioner.

Based on the fact that I pulled it out, I'm unsure what this means.

[herennow]

That sound is too high-pitched to have anything to do with rod, I think. I'm guessing it's around 50 HZ which would mean it's linked to cams/ top end,  which run it twice the speed of the engine.

How were your exhaust valves? Was the oil and filter clear when you drained it, wondering if maybe the rotor/ stator threw a magnet

I'm trying hard to imagine what could cause a sound like that that would come and then go and then come again without major damage.
Maybe try to pick up a second hand cam chain Tensioner and see what happens? But before that I would take yours out and thoroughly study it before deciding what to do.

[wheetbix]

I've ordered a manual CCT which should come this week which I was going to try. Someone I showed the video to said it could be a clutch spring.

They said to pull on the lever and it would be hard to pull, which I did. I'm unsure if it's actually the problem because it's somewhat hard but since I have had the bike it sort of feels the same.

If the cam chain tensioner doesn't fix the problem I'll be draining the (fresh  ) oil and pull the clutch cover off to inspect.

Both exhaust valves were within spec, the intake were too tight. Oil didn't seem to have metal, checked with a magnet and the filter looked pretty normal for the service interval

[herennow]

Can't imagine how a clutch spring would make that noise. If the screw /spring had come loose. The noise would be there all the time...

[Armandorf]

sounds like its out of time,cam chain skipped some teeths, turning the engine by hand is easy? i accidentally skipped a teeth building the engine an it sounded like that, but it was one rotation by hand.
""
2. Took the cylinder head cover off and checked the camshaft timing marks were not out of sync and stayed in sync for a few rotations of the engine
""
did you check the crankshaft position also?

[wheetbix]

The RT mark kept alignment with the camshaft timing marks. It does sound like it has slipped timing but then why does the sound come and go when the engine is cold?

I can get another video of it coming and going.

Other than checking timing marks is there a better way to verify timing is all good?

[chris900f]

The exhaust is pretty loud so its hard to tell, but it sounds like a rod bearing.

Check for exhaust leaks at the cylinder head. Kind of a long-shot, but an easy fix if it's just loose bolts or bad exhaust gasket.

[Armandorf]

If you have rod knock the piston should have play, turn the engine by hand and push the piston down when the rod is pulling it down, so if there is a slack you can somewhat measure it, use a tool of your convenience and safety to insert trough the spark plug hole, a thick wooden stick, a screwdriver with something in the tip so it doesn't scratch the piston(not for the scratch but for the loose metal)

[wheetbix]

Update: I decided to double check the timing so I opened everything up. Timing was definitely good and I decided to give the crankshaft a whirl. I noticed that when the left intake lobe was trying to open the intake valve it was quite hard to turn, not sure if that's normal but rotation around any other point seemed smooth.

I also paid close attention to the chain as it went around... and found this:
https://imgur.com/a/A5jEtOr
(Sorry, uploading an image wasn't working so I uploaded to imgur, I hope that's okay)

It appears to be a sheet of metal, not sure where from. My friend has an endoscope that I'm planning to use to look at through the spark plugs.
Speaking of spark plugs, I did renew them and I have run the engine a few times. When I took out the new ones, the left cylinder was matte black.

I'm still unsure what the problem is.

[wheetbix]

Another update while I wait for the borescope. I used my phone camera to look through the spark plugs and saw this indentation on the left piston. It looks old but thought I'd share in case it means something

https://imgur.com/a/4c4I0Zm

Neither the old spark plug or the one I used to replace it seem to have any signs of being crushed, which makes me think this is maybe from a previous owner installing a too long of a spark plug.

[Armandorf]

a triangle is stock for the gs pistons, indicates the front, points towards front wheel.
maybe what you are seeing is only carbon buildup

think that something of the combustion chamber cant get to the crankscasse if it is no by the piston rings, so so you have a low end problem


you are missing the outer portion between cylinder walls and piston rings.
Logically from the outside what you show is the only visible part till you get a camera down there.

I want to buy a borescope but im afraid they are too bad, and i have to open everything anyways...

dont run it again, you should open side covers,magneto could have metal shearings,smaller one) and clutch side(start from this, the bigger one) ,check balancer half-bearings. they are in the most front part of the engine, towards the oil filter.
also check the pump

[wheetbix]

I thought it was an orientation mark!

I got the borescope and checked left and right cylinders and valves, nothing is bent. I also did a smoke test by closing off both valves and blowing smoke through the spark plug.

The smoke didn't leak out of the valves so I think you're right that it's a bottom end.

Aside from the bottom end I think the only other thing I haven't checked is bad fuel and bad carbs, what are the chances this is the problem?

I'm not sure but it's a cheap enough check that I'll do it first, then I'll start opening up the button end.

[Armandorf]

check oil pickup screen
,it is evident something pretty bad has happened.
these motors are usually though, but you may have a blocked oil gallery/jet/passage by that sheared metal

[wheetbix]

I dropped the oil pan and you can see it here. I used some degreaser to clean out the oil so it was easier to see the damage.

[Armandorf]

goats, magnet epoxi crumbling off+ sheared metal,you have a lot of work ahead, take a picture of the bottom of the engine to see the oil pickup screen.
then the side covers.