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Discussion Starter #1
Hi,
Was riding a 2016 9T with 9000 miles on it.
I was on the highway going fast (not usually) and suddenly noted a little power fall.
After that the engine noise changes and seems the bike does not work so fine.
In the workshop they tested the bike and they told me that everything seemed ok.
After ride about 50 miles, decided to measure valve clearances.
All clearances on right side was ok, but wen opened left cover valve discovered that the semi sphere shim of the upper exhaust valve is out of the rocker.
How is possible the semi-sphere fell out?
Circ clip is still well attached.
Thanks and excuse for my english (not my native language).
 

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Discussion Starter #2
Upper exhaust rocker directly on the valve tip, no semi-sphere shim.
Semi-sphere fell out in the drain tray.
 

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I for one am waiting for a reasonable explanation from the A wrenches on this site. I am running rocker / valve train malfunction scenarios through my head and am drawing a blank. The picture shows the valve stem and spring intact.
When was the last time that valve was adjusted?

Glad it wasn't a catastrophic failure.
 

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Hi,
Was riding a 2016 9T with 9000 miles on it.
I was on the highway going fast (not usually) and suddenly noted a little power fall.
After that the engine noise changes and seems the bike does not work so fine.
In the workshop they tested the bike and they told me that everything seemed ok.
After ride about 50 miles, decided to measure valve clearances.
All clearances on right side was ok, but wen opened left cover valve discovered that the semi sphere shim of the upper exhaust valve is out of the rocker.
How is possible the semi-sphere fell out?
Circ clip is still well attached.
Thanks and excuse for my english (not my native language).

My best guess would be the shim slipped out when someone was reinstalling the rocker arm and they didn’t notice. They are pretty slippery. Then they reinstalled the circlip and buttoned it up. 9000 is a little early to be swapping shims, but I guess it’s possible. I’d echo @Juice in asking when it was last serviced. That’s likely gonna be your culprit.
 

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Discussion Starter #6
All from factory, valve cover never opened before, motorcycle only has 9000 miles.
Motor oil and filter changed 1000 miles before.

I perceived when the engine fails, running at high rpm, but clearly under red line.
After that, engine noise increased and didn´t work so well, but not so clearly as to be sure.

Ran about 50 miles before opening.
Here the damage in the valve tip due to run without the shim.
 

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All from factory, valve cover never opened before, motorcycle only has 9000 miles.
Motor oil and filter changed 1000 miles before.
The valve covers would have been off at least once in the last four years to check clearances. It’s in the 6k service. Are you the original owner?
 

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Discussion Starter #8
Yes, I´m the first owner, but Bmw says check clearances al 20000 Km.
I checked all valves now, all are ok.
All 4 exhaust valves : 0,36 mm and 3 Intake : 0,18 mm and only 1 intake : 0,21 mm.
I measured the damaged valve with the old shim but sure I will replace it.
 

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Yes, I´m the first owner, but Bmw says check clearances al 20000 Km.
I checked all valves now, all are ok.
All 4 exhaust valves : 0,36 mm and 3 Intake : 0,18 mm and only 1 intake : 0,21 mm.
I measured the damaged valve with the old shim but sure I will replace it.
It’s every 6k, so the 12k (20,000km) should have been the second check. If the valve covers were truly never off then I’d say the shim was never installed from the factory and you’ve been riding on the top of the valve this whole time. I don’t see any scenario where the shim slips out with the rocker arm in place and the circlip intact. It may be the oversight went unnoticed until the loose shim was jostled out of place during riding and interferred with normal operation.
 

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Ran about 50 miles before opening.
Here the damage in the valve tip due to run without the shim.
👀😱🧐🤨

I’m shocked, these engines are typically bullet proof and your miles are still low. BMW should definitely pick up the tab on this.
 

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Discussion Starter #11
It’s every 6k, so the 12k (20,000km) should have been the second check. If the valve covers were truly never off then I’d say the shim was never installed from the factory and you’ve been riding on the top of the valve this whole time. I don’t see any scenario where the shim slips out with the rocker arm in place and the circlip intact. It may be the oversight went unnoticed until the loose shim was jostled out of place during riding and interferred with normal operation.
Maybe it was a assembly defect, I dont know, I dont perceived any problem until now.
Now, my doubt is if there can ocur another time due to any ocult problem.
Also, I dont know if the valve tip damage can cause a problem engine. I need to change the valve?
 

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Maybe it was a assembly defect, I dont know, I dont perceived any problem until now.
Now, my doubt is if there can ocur another time due to any ocult problem.
Also, I dont know if the valve tip damage can cause a problem engine. I need to change the valve?
Can't hurt. These shims don't pop out spontaneously. Considering that you are the original owner I'd say too much fine German beer the night before for the shim man.

Why pay someone else to fup your bike when you can do it yourself.
 

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Maybe it was a assembly defect, I dont know, I dont perceived any problem until now.
Now, my doubt is if there can ocur another time due to any ocult problem.
Also, I dont know if the valve tip damage can cause a problem engine. I need to change the valve?
I would bring the bike to an authorized dealer and give them the details. It’s unlikely, but possible they’ll do something for you even out of warranty and despite your failure to follow the service schedule. Since you have pics, and can attest the valve cover had not been off since original delivery, it may be a case where they work with BMW to warranty the work. It’s an outside shot, but worth it. My best guess is still that the shim was never installed, was sitting somewhere in the head, and at some point recently was jarred loose, wreaked havoc, and then resettled somewhere else. That would explain why you hadn’t noticed before and why the workshop you took it to felt everything was ok. I would probably have the valve replaced and the whole head looked over - who knows what damage it could have done bouncing around in a running engine. Best of luck.
 

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I have never heard of this happening before with one of these engines. I'm inclined to think Karamazov may be right in thinking the shim sphere was incorrectly seated and settled in the head unnoticed. Looking at the pic of the valve stem I don't see much in the way of damage other than the edges of the stem. I'd be inclined to put the shim back in, measure for clearance, if within, run the engine, do a compression test, if good keep going, if not good then head comes off and remove that valve, check seat condition and fit a new valve. Let us know how this goes for you. (y)
 

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Inspected the shim.
It appears no new then maybe not a factory assembly problem.
It might look like that from being bounced around for quite a while.
I don't know enough about these shims yet, I'm a nugget. If these shims are stamped with their size I would like to see it miked and compare the reading with the size identification number.
 

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Discussion Starter #19
Finally, I only replaced the rocker arm and the shim.
Everything works fine but I have lost the confidence to go fast with the bike.
I would like to know how and / or why this happened to be confident.
 
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