1150 gs Rattle/chirp from left cylinder

[Mr G]

Hi there, Thames valley member Gareth here, a new noise that I cannot find mentioned anywhere.

https://youtu.be/tgCJYTo2U3c

Anybody have any clue what this noise could be before I start taking it apart? I've changed the left cam chain tensioner with a new one (an uprated one was already fitted). I've checked the rocker clearances and they are fine. It's more of a chirping noise rather than a knocking and is most noticeable at the front of the left side of the bike.
The bike is a 2004 1150 gs adventure with 96,000 miles on it.

Things I know so far.
Its noticeable in the video, the noise continues even when riding along but is most noticeable when accelerating.
The noise has grown from perceptible to noticeable to noisy fairly quickly.
It doesn't change if the bike is hot or cold
When I changed the tensioner It clattered a bit (different noise) and the quietened down straight away.
The alternator belt looks fine, no bits hanging off and it doesn't feel loose.
Oil light goes out straight away even at Idle but the light comes on within a few seconds of stopping the bike.

It almost sounds like something rubbing but I couldn't see any damage under the rocker cover, nothing felt like it had too much play and when I fitted the new tensioner it had enough oil pressure to push oil out past the crush washer until I nipped it up a bit more.

Hope some one can suggest something from the video, my plan for tomorrow is to inspect the timing chain and guides as best I can and possibly pull the pushrods for inspection and just in case try it with the clutch pulled in which I haven't tried yet. The oil light going out straight away worries me most though.

Thank you

Gareth

 

[Slipperyeel]

That's a hard one to work out via forum. But as you've said, it does sound a little like the chain running over the tensioner. It doesn't sound metallic.

Did you replace the tensioner as a part of your attempts to lose this sound? Or did it start after you replaced the tensioner?

It really is hard with sounds, I mean trying to diagnose them. But I think your idea to get the rocker covers off and take a look at the tensioner blades is a good one. They do break.

One thought, you didn't undo the bolt that secures the tensioner blade? It's south of the tensioner itself, on the back of the head, inboard of the throttle body. I don't have an image to hand. But if that was taken out...it's a bugger to refit, but there's also a chance it could be refitted without actually passing through the blade mounting hole...meaning the blade is just waggling around in there...

You need the likes of Steptoe or Mikeyboy...I'll bet they've seen this before.




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[Mr G]

thanks for the reply, yes I replaced the tensioner to try and get rid of the noise. The noise is exactly the same before and after I changed the tensioner. No I haven't removed any mountings for the guide blades or anything yet. I couldn't see anything wrong or rubbing under the rocker cover but I shall have a more in depth look tomorrow. and try and eliminate a few more things.

 

[Slipperyeel]

Sorry I can't give a nice tidy answer.

There are all sorts of things that cause noises - though admittedly, they're not what your video sounded like - but a leaking exhaust port (where the header bolts into the head itself) can make noises. So can intake leaks but I'd have expected you to notice running problems if that was leaking.

Your video suggests the sound is coming from the head area,rather than the alternator for example.

It's just a wild thought. But the oil filler plug is near the cam chain. Maybe take it out and check something weird isn't going on with that reaching down into the chain. God knows why it might be. But it's free and easy to check!

Right now I'm thinking a broken tensioner blade... but of course I'm just guessing based on your video. Steptoe has documented on here how to replace the blade without open heart surgery on the motor. So don't panic if that's what it turns out to be.

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[Mr G]

I'm gathering ideas today so all are welcome. Some suggestions to try:
Leaking exhaust seal, leaking head gasket, loose spark plug (checked), cam chain tension blade, valve guide, alternator belt, throttle body synch.

So tomorrow I shall check for exhaust leaks, carry out compression test, start the bike without the alternator belt on, and also check that nothing is fouling the throttle cables or they are not frayed.

 

[Homer]

I would be looking more toward the v belt first.

 

[otruk]

Does sound like a belt for the alternator.

 

[(RIP) Bin Ridin]

Belt chirp on 1150GS had me thinking I had a head gasket blowing but in the end - it was the v-belt...

 

[Slipperyeel]

Interesting. Didn't sound like alternator area to me. But I'm listening to it on my phone.

Very interested to hear the solution to this one! Keep us posted!


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[wust588]

Could it be coming from the pushrods? As I understand it, the earlier type gave trouble.

 

[GS Addict]

Mine made the same noise and it was the alternator belt - it was old and had a 3" thread hanging off it, banging into the front cover.

 

[oblertone]

If your bike is fitted with OEM crash bars it's worth checking the mount points as the welds will part over time and produce a seemingly engine related noise.

 

[(RIP) Bin Ridin]

The noise you recorded sounds a bit deep for a belt which I recall as more of a chirp.
Could you remove the belt and run the engine, just to eliminate that?

Your noise is reminding me of ignition knock.....
Could anything have happened to cam timing during the tensioner change?

 

[Steptoe]

Oh dear. It could be the cam chain tensioner guide rail that's broken.

It usually happens on the L/H side.

 

[Mr G]

ok well I checked the timing chain, guides and tensioners left and right and all looks ok from the pictures. I checked the head bolts are all tight and on close inspection could not see any damage under the rocker cover. The bike made the same noise with the alternator belt removed so Its not the belt or alternator. I did how ever find one exhaust stud has rusted off so I'll replace that first as it easier noisier around the front of the cylinder. I didn't manage a compression check as the battery was a bit flat and would start it again.
So, new exhaust seals and stud ordered so we shall see if that sorts it out.

Tanks for the advice, I shall keep you posted when the bits arrive. Just have to remove a broken rusty stud from the head now.

 

[Slipperyeel]

It's hard to see much from your pics. But from posts I've seen in the past, the guide can split down at its fixing point making it hard to see, but allowing it to waggle/flap around beyond what its supposed to...

I'd take a long look at those exhaust studs and decide if you really need to touch them. That could end up an entirely separate can of worms!

My old 1150 had a nut missing off each header. I never ever bothered touching them. Never a single leak from them. Same was true on an old ST1100 I had many moons back.


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[Andy63]

Sounds like thiis guy had a similar issue https://www.youtube.com/watch?v=Yu36vhL6j4c and fix if it is the same knocking noise.

Edit after comparing videos your is significantly louder so may not be the same issue.

 

[Mr G]

I've got more pictures of the chain guides but It required 3 hands to point the camera and operate the laptop to take the picture! All the mounting points look good so I'm happy its probably not the timing chain or guides. Many attempts at welding nuts on the remaining stud failed each time as the stud sheared off at the weld. Hopefully the new stud will arrive today so I can use it to check the depth before I drill it out and Helicoil it. Thanks Jersey GS, that's a video I had seen which sounds similar so If the exhaust stud and gasket do not fix it the push rods are next on the list. I would check them now as I can see they are the original type but I don't want to undo the head nut to take them out if I don't have to.

 

[Mr G]

sorry, Photo is upside down.

 

[The Other PaulG]

plus 1 for the left handed drill idea.

I once watched an engineer use one and the very corroded stud came out with very little drama after not much drilling.

He used some penetrating fluid, then the heat/ vibration / torque of the drill just popped the stud out.