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Discussion Starter · #1 · (Edited)
Hello Experts!
I have a 2021 BMW RnineT Scrambler. Now mileage is 4000 km. But for more than 2500 km I have been suffering from a strange metallic sound when accelerating.
At the same time, it doesn’t matter which gear I’m in: 1,2,3,4, you can still hear a metallic sound when accelerating. It is especially pronounced under load. For example, if I am not traveling alone and / or on an offroad. I took the bike to the dealer. At first they said that they did not hear, and then they nevertheless took me for an inspection. In the end, they gave this answer (I'm attaching below).
I am attaching a Video of SOUND (sorry for the quality) I don’t have a camera, so my wife filmed it on the phone as best she could =)

I love how this bike looks, but unfortunately the quality disappointed me. Brembo brakes squeak all the time. At 3500 km, I replaced the pads and brake discs! New ones - they creak again =))))
But to hell with them, but what kind of metallic sound is this when accelerating, can someone tell me? I know there is answer from BMW, but I don’t believe I will have to live with it :( This is quite annoying to ride with this sound :(
BMW Motorrad Answer:
A noise based on irregularity in turning of the engine at high load and low revs.
Basically it is the engine does not feel well at full or high load in this rev range. The design of inertia is always a compromise between low and high revolution performance and the inertia here is relatively low to perform better at higher revs.
At high load and low revs the turning of the crank shaft tends to be irregular like here.
This irregular movement creates resonances and this is basically the noise. You can't do anything about it. It is based on the chosen inertia of the crank drive. Less load or higher revs are the key.
Since it is a kind of resonance the rpm range is very close. It could be that other bikes have it less pronounced or less noticeable and it could slightly grow with mileage at the beginning. Components run in and clearances slightly grow naturally at the beginning. It is nothing severe and I have noticed this in all the years we build K2X engines now (since 2004). It is nothing serious or dangerous at all.
 

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What’s the grade of petrol you buy for your bike …. Is it a pinging sound that modulated louder the harder you twist your wrist. Do you know any other 9T owners that you can compare notes and see if they feel the same way …. Low grade gas or heavy ethanol content could be a contributing factor …. Flush the tank and top off with the top grade available and see if that’s a game changer ……. GoodLuck …… Cheers ……..Blitz
 

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Discussion Starter · #3 ·
What’s the grade of petrol you buy for your bike …. Is it a pinging sound that modulated louder the harder you twist your wrist. Do you know any other 9T owners that you can compare notes and see if they feel the same way …. Low grade gas or heavy ethanol content could be a contributing factor …. Flush the tank and top off with the top grade available and see if that’s a game changer ……. GoodLuck …… Cheers ……..Blitz
Well, yes! This pinging is louder if I twist the accelerator handlebar. But off course this is very short pinging sound, as you can hear on video. About gas, last time I was using 95. In Europe we have good gas, but I will definitely will try 98 next time. This sound is killing all pleasure of ride :(
 

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I admit, I couldn't hear it anything in your videos. But then again, nobody could hear the "ringing" sound in a video I posted about a metallic sound with my R1200R, when I could hear it plain as day! Again, different bike, but at first I was sure my bike was "pinging". That bike still has that sound 10K miles later, and I have decided it is a resonance that just happens at a particular RPM, and I just ignore it.
 

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Does the sound persist if the bike is in neutral? If you apply throttle in neutral and it’s still present, maybe try pulling in the clutch. If the noise disappears, it may be driveline related. My K1200 makes all kinds of racket until the clutch is pulled in
 

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Discussion Starter · #6 · (Edited)
I admit, I couldn't hear it anything in your videos. But then again, nobody could hear the "ringing" sound in a video I posted about a metallic sound with my R1200R, when I could hear it plain as day! Again, different bike, but at first I was sure my bike was "pinging". That bike still has that sound 10K miles later, and I have decided it is a resonance that just happens at a particular RPM, and I just ignore it.
Omg, I don’t think I can live with it :))) The sound is very similar to the, when you don’t give enough gas against the clutch. If you have headphones, try it. I can hear it clearly:((
 

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Discussion Starter · #7 ·
Does the sound persist if the bike is in neutral? If you apply throttle in neutral and it’s still present, maybe try pulling in the clutch. If the noise disappears, it may be driveline related. My K1200 makes all kinds of racket until the clutch is pulled in
Ghm… actually it’s not! When on neutral even if I use throttle there is no any metal sound. Only on load. Off-road, and with passenger.
 

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I will tell you this. Higher compression engines when lugged well give that asynchronous rattle. Slight change in amplitude but very intermittent and sputtery. I can lug my 11-1 compression v twin and get that exact same sound. So yes in a enlarged explanation the guy was right. Low rev and high load will produce that sound. I would check the valves also for proper adjustment
 

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If it’s not in neutral and only shows up in gear…I vote for driveline issue. If the clutch in or out has no effect, then transmission or driveshaft, final drive maybe. Your fuel octane is way better than what I’ve run in mine with a full, no cat exhausted, and my bike never pinged…even under heavy load
 

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Discussion Starter · #13 ·
I'm with Blitz - bad fuel! Maybe dilutet due to the high petrol prices. Same Patrol Station the last 2500km? Trustful??

ed: the noise is in the vids audible
Well, it’s Circle K. Never had any problems with this petrol station on any on my cars, motorcycles…:/
but I will try to go up with 98
 

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7. Engine Ping

Engine ping or pre-ignition is caused by hotspots in the cylinder igniting the air-fuel mixture before the spark plug. The two flames collide, boosting the pressure. This is usually caused by low-octane fuel in a high-compression engine, but it can also be due to carbon deposits, incorrect spark plugs, or overheating. Most people find the solution by moving up one grade at the pump. Deeper problems may require professional attention.

Bad gas could be the issue. When the engine is running good nail the throttle at low rpm and you will create the same noise.
Try the highest octane that you can get.
 

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I can certainly hear that and its not something I've heard before on my Ninet.

I'd be worried about it too and I don't agree with BMW that its nothing to worry about as I couldn't live with it.

Sell it.
 

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Something is not correct. Live with it?? 100% wrong answer. I was figuring out my low RPM roll-on thresholds the first week I had the R9T. I lugged the motor for a second or two a few times and had the same sounds. Anyone want to try some engine lugging and roll-ons for input here? I'm guessing you are not seriously lugging the motor. Bad gas will exaggerate the problem significantly.
 

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Discussion Starter · #18 ·
I will definitely will try the better fuel, hope this will help. I have find out that on GS forum a lot of owners have the same issue..
 

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Discussion Starter · #19 ·
7. Engine Ping

Engine ping or pre-ignition is caused by hotspots in the cylinder igniting the air-fuel mixture before the spark plug. The two flames collide, boosting the pressure. This is usually caused by low-octane fuel in a high-compression engine, but it can also be due to carbon deposits, incorrect spark plugs, or overheating. Most people find the solution by moving up one grade at the pump. Deeper problems may require professional attention.

Bad gas could be the issue. When the engine is running good nail the throttle at low rpm and you will create the same noise.
Try the highest octane that you can get.
When the bike is hot (after off-roa) you are right the sound is even worse :(
 

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Agree with the majority from the videos what I hear is a mechanical rattle that sounds like pre-ignition to me and it will get worse if the engine is really hot

Difficult to be certain as RPM & throttle position are unknown, but from the videos it sounds like you're coming off the throttle to low RPM then gassing it. You can also hear the noise reducing once engine revs start to build.

I'm in agreement with @BlitzSchnell & @Juice I'd drain the tank and fresh fill with super, check the book for the recommended grade. Sure you can run regular but I'd normally only do that if super wasn't available and then I'd keep the revs up to avoid low rpm/large throttle opening. (remember US Octane numbers are MON, europe is RON. A quoted Europe Octane would be a lower number in the US)

Although the BMW is a twin it's not a torque monster at low rpm and runs best when the revs are higher.

Guzzis are very similar & you'll always see on their forums, time after time "Don't lug it, rev it".

Newer bikes may also be worse due to leaner mapping of Euro 5, but I don't know
 
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