Ugly ticking sound from engine, 2013 Tiger 800 XC

[Rauno_N]

Hello to all,

Unluckily dropped the bike and it fell partly in water. Fell on the right side and water level was near the speedometer, so i'd say 1/3 of the engine was under water.
Tail was higher and out of the water. Engine stopped really fast and i didn't even have time to think to switch it off. I was almost standing still in 1 st gear on a really narrow beam over a small river/ditch and lost the ground under my foot, so bike died immediately since i fell off and released the clutch.
Bike was on the side around 5 min until i could get it out of the mud.

Intake was try, no sign of water in airbox. Started the engine and immediately got this strong tick coming from the engine. Sound is stronger on the right side, but really hard to identify if it comes from upper or lower part. Drained the oil and their was no sign of emulsion/water in there.
Engine starts immediately every time, just like it's used to. Idle rpm is normal and by hearing all the cylinders work smooth, throttle response seems normal, at least in neutral. Haven't tried to ride it. Pulling clutch lever does not change the sound.

Has anybody had similiar case or similiar sound from the engine ?

Does this engine have a knock sensor ?

Here is video of this:

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[Georgeinabz]

Definitely metallic noise ,not good .
Hard to tell over the video try cam chain tensioner ,but to me it sounded like bad valves , it maybe that on of the cylinders hydrauliced with water and bent a valve. I wouldn’t start any more until you get to the route of the problem.

[AvgBear]

Originally Posted by Rauno_N

Does this engine have a knock sensor ?

No

I'd remove the cover on the R.H. side of the engine and give the cam-chain and tensioner assy. a good look.

[Rtwo]

They have a tip over sensor, that's why the engine cut

[Stevie.P]

As Rtwo says, the tip over switch would have rapidly shut the engine down and (with the obstacle of a cat also) likely reduced the risk of water induction to a minimum.
To me, the running of the actual engine sounds like it is running on all 3 cylinders as normal, no loss of cylinder misfire detectable.
It actually reminded me of the similar sound my Bonnie makes if I fire it up with no exhaust pipes fitted in the head. I would take a really close look at the exhaust system for a small fracture, particularly around the head and header pipe area (especially welds) possibly caused by the sudden shock of being dunked in cold water. 

[chuckxc]

Strange one. Intuition only, but I have heard this on my 2012XC occasionally after a long unused period, and I have attributed it to a temporary lack of oil in the timing chain tensioner. From memory I think this is a hydraulic tensioner. Could the drop have affected this, not sure, but the pre-tension procedure is simple and might be worth a go.

[Bladerunner99]

I would suggest valve or cam chain tensioner!

[Rauno_N]

Thank you for the replies.
My first doubt was also cam chain tensioner. Altough after removing the cam chain cover everything was fine, chain was properly under tension and no issues visible.
After that removed the gas tank and cam cover, timing signs on cams and crank were correct, no way the chain could have "hopped over a tooth". Measured the valve clearances and all were correct, in my opinion this should already indicate a bent valve ???
Just in case got a brand new OEM cam chain tensioner from local dealers stock, installed and assembled everything again. Sound was still the same so problem not found.
Next step removed the sump and found lots of aluminium particles there, frightening but at least tought now i am on to something...
Dropped the engine a couple of cm to remove the cylinder head, pistons and valves were fine, no sign of contact between them.
Then removed the engine from the frame, took it apart and removed the connecting rods from crankshaft. No it was getting weird since there was no damage at all on pistons, crankshaft main bearings or connecting rod big end bearings. Didn't remove the pistons from the connecting rods, since the CR upper bush was moving smoothly and tight.
Main bearings and CR lower bearings were visibly fine, however just to be sure measured the clearance with plastigauge method, result 0,025 mm which is totally normal acoording to manual.
Now it was clear the aluminium particles found in sump had to be there already earlier. Later figured out that last owner had broke the clutch so bad drum was also broken. Since all the aluminium parts were not damaged, this pieces had to be there since clutch breakdown (approx 8k km earlier). He didn't remove the sump so this makes perfect sense that some pieces remained in the engine.
Every corner and shaft inspected, no sign that these aluminium particles could have made a damage in the engine. Measured the piston ring gaps, matched with manual normal values. Measured cam chain length, also in limits. Checked the oil pump thoroughly according to the manual. Made a leak test to cylinder head by turning it upside down and pouring gasoline on the valves, no sign of leak.
It was really strupid feeling to assemble the engine without finding any issue, but best hope was that the aluminium pieces were stuck between some moving parts and this caused the mechanical sound.
After full assembly and firing up the engine..still the same sound, no changes.

Only thing still undone is removing the valves from the cylinder head. Is there any chance the issue is there if we now that there is no leak and valve clearances are correct ?
Damaged/broken spring etc?

To sum up what has been checked:
Valves and pistons have no sign of damage (valves not removed from the cylinder head)
Cylinder linings have no sign of wear or damage
Connecting rods, crankshaft, main bearings and big end bearings have no damage and clearance measured with plastigauge
New cam chain tensioner, cam chain measured and fine, chain under proper tension
Timing correct (has been checked after several engine starts and still correct)

There is one theory that 3 rd cylinder suffered cold stress after falling in water, cylinder shrinked with sudden cool down and damaged the piston. Piston was visibly checked but not measured or inspected deeper with a magnifying glass from microscopic cracks. This is a thing that occurs on BMW-s, so potentially possible according to my mechanic.

Forgot to take pictures of pistons, crankshaft and connecting rods sadly, added a picture of cylinder head after grinding.

Open to any ideas what to still check, really frustrating and complicated case for even real experienced mechanics.

Pieces in the red cap were the biggest foundings from the sump:

Cylinder head after gasket surface grinding.

[Stevie.P]

Originally Posted by Rauno_N

There is one theory that 3 rd cylinder suffered cold stress after falling in water, cylinder shrinked with sudden cool down and damaged the piston.

I doubt that as the hot coolant in the cylinder water jacket would have dampened the shock level substancially.

Did you check the exhaust over for cracks just in case (as suggested previous). I've heard small exhaust leaks cause squeaks that can give the impression of a metallic sounding noise and the hot exhaust would be more likely to suffer a stress (fracture) issue than the cylinder/piston.

[Georgeinabz]

With all that bits in the red cap it would be a good idea to check the oil pump rotor & flush the oil ways👍