CB650R Buzzing / Resonance Noise 5.5K to 6.5K RPM ('19 CB650R)

[thatyanguy]

Hey folks - sorry for long absence. Needed an internet break that turned into an internet sabbatical.

Anyways - I'm 90% positive it's the key socket for me - specifically, the metal pins inside the keyhole vibrating, as when I tap the key (don't hold it too strongly just in case....) the sound decreases. I've pulled the plastic shrouds off and re-installed, no change. Don't believe it's the header as that would be a bit more noticeable and across a wider RPM range. The only thing the honda tech told me before he charged me a stupid amount of money for 10 minutes of his time was: "It's a buzzy bike, they're all buzzy" and "sounds normal to me".

Honestly, I've given up trying to deal with it - just try to focus on and enjoy the ride. Seems like we have a various collection of issues related to the general I4 vibrations. Oh well...

 

[FogDucker]

My bike is doing its winter sleep right now, but I did manage to get an audio clip of the sound.
Listen with headphones for the best effect.
EDIT: (listen to this on your smartphone). I just listened to the clip on my PC and could not easily hear the static/buzzing sound - using the pc speakers - Maybe my pc speakers are conditioning the sound somehow - filtering out the harsh frequencies.... When I browse to this site and play the clip on my phone - the sound in question comes through loud and clear --- exactly how it actually sounds when riding the bike.
The static buzzing sound happens at the higher rpm's.

Sounds like an alternator issue to me.

 

[Atucker]

My annoying / unusually buzzing noise disappeared as I put on miles and broke the engine in. The only time I had any sort of unusual noise after the 1500-2500 mile mark was when the top plastic that covers the tank had come loose from the velcro on the side. Snapped that back and it's been quiet and smooth since - well as smooth as any other inline 4 I've ever owned.

I do tend to agree with the mechanic that these are just buzzy bikes, but no more than any other small inline 4.

 

[thatyanguy]

Sounds like an alternator issue to me.

If it's the alternator, I would (and pardon my ignorance here, not a very mechanical person but slowly dipping toes into the water), the noise should be directly tied to RPM, regardless of engine load - as the speed at which the belt / wtv driving the alternator is not load dependent. My buzzing issue relies on the engine being under load (which may not change the RPM, but it does change the fueling), and the fact that there is nothing between 0 to about 5.5 / 6, then it comes on for a couple of thousand RPM, and then it goes away again suggests that this is a resonant frequency causing the noise - which would make sense under the "keyhole tumbler" theory.

But it could also be anything - there's other wierd noises the bike makes (like the instrument panel whistle at certain speeds), so I'm sure what we have are a collection of issues manifesting similarly.

 

[FogDucker]

Put it on a stand and record it

 

[Atucker]

No alternators or belts on the CBR650. Charging is via a stator. Any noise from it would have to be really severe to be heard over the rest of driveline noises under the crankcase covers.

 

[FogDucker]

No alternators or belts on the CBR650. Charging is via a stator. Any noise from it would have to be really severe to be heard over the rest of driveline noises under the crankcase covers.

Well yes. I correct my self. Stator. Got sucked into cars world!
A stator can get noisy too. Specifically the part that is connected to the flywheel.

 

[Atucker]

That's a bit more than buzzing. Sounds like a coffee grinder full of gravel. I'm assuming the person in the video had no problem diagnosing that problem!

Back the CBR650 - I'm convinced that the buzziness is two fold; normal for the bike, and gets much less as the miles get added. I've now got ~4000 miles and it's smooth as glass at all RPM's. Bike has done a complete 180 from when new.

 

[xorbe]

What I want is the 15000 rpm buzzing of the CBR600 in my 650 ...

edit: so there was a CBR600 article yesterday, not only is the bike basically out of date, but imho the 650 looks better. I don't want more power, just the revs, lol.

 

[icemankent]

Wow, so no definitive solution to this super-annoying sound yet ?
It is loud-enough when it happens - that it sounds like it is more than just a random (vibration) - but rather a mechanically-produced sound.
I can't find it just by riding, and pressing on random things to see if I can find it !

Not sure what else to try - as it happens (only) under load - (revving it in neutral does not produce the sound).

This sound is detracting from my enjoyment of riding the bike - as it interferes with the beautiful intake sound......Sigh.

 

[Atucker]

Wow, so no definitive solution to this super-annoying sound yet ?
It is loud-enough when it happens - that it sounds like it is more than just a random (vibration) - but rather a mechanically-produced sound.
I can't find it just by riding, and pressing on random things to see if I can find it !

Not sure what else to try - as it happens (only) under load - (revving it in neutral does not produce the sound).

This sound is detracting from my enjoyment of riding the bike - as it interferes with the beautiful intake sound......Sigh.

How many miles do you have? The noise I believe you're describing based on my experience went away as it broke in.

However, if you're just talking about a general buzziness / resonance I'm more convinced than ever that its the result of incorrect octane rating. At 87 octane my bike is glass smooth, but I recently changed out the exhaust and figured why they heck not try 93 again. And instantly the bike is a buzzing vibrating mess! It's like a light switch; increase octane level - bike vibrates like crazy. Go back to 87 and it's right back to its normal smooth self. Never again!

 

[icemankent]

Roughly 17,000 Km on it.
I run 93 octane (Shell) - only because it has NO Ethanol added.
If I go to any other lower grade of gasoline, then I am stuck with an Ethanol blend.
I suppose it would not hurt to try running it with 87 - as an experiment - but I am doubtful that's the issue.

 

[Atucker]

Roughly 17,000 Km on it.
I run 93 octane (Shell) - only because it has NO Ethanol added.
If I go to any other lower grade of gasoline, then I am stuck with an Ethanol blend.
I suppose it would not hurt to try running it with 87 - as an experiment - but I am doubtful that's the issue.

I wouldn't worry about the ethanol. It's designed to run on an ethanol blend as are all modern motorcycles. Manufacturers are acutely aware of what fuel is available and design for it. What it's not designed for is to use an octane higher than the recommendation which in the US is 87 octane.

 

[miweber929]

I wouldn't worry about the ethanol. It's designed to run on an ethanol blend as are all modern motorcycles. Manufacturers are acutely aware of what fuel is available and design for it. What it's not designed for is to use an octane higher than the recommendation which in the US is 87 octane.

There’s a lot to worry about with ethanol beside running issues. The biggest concern? It attracts moisture. So if your bike sits at all, even as little as a week you will have moisture in the tank with is hard on fuel pumps, fuel sending units, wires, fuel lines, the tank itself; basically anything the fuel touches will start to corrode whether you see it or not.

And the bike is absolutely designed to run higher octane than 87, you just won’t see a benefit from it. Unless there are other factors: the higher tier fuel generally has more additives in it to start and I run non-oxy premium gas whenever I can in all of my vehicles, some call for premium (my Ducati and Jeep both require it) but others because they sit between uses and there’s no need to add stabilizer every ride. In my truck, a ‘16 Silverado with the 5.3l, I run non-oxy premium because it’s a direct injection motor so it helps to keep the combustion chamber clean and is driven maybe once a week or so.

 

[Atucker]

I disagree that it was designed for higher octane. If it was designed for higher octane it would be able to take advantage of it or require it as other high compression engines do. There are definitely engines that are spec'd to run on 87, but make specific note that they have the programming and sensors required to advance timing and take advantage of the increased octane and as such increased HP. The CBR650 just isn't on that level and probably never will be at least in the foreseeable future.

I do tend to agree about top tier having more additives, but unfortunately even with premium the ethanol remains at the vast majority of stations.

 

[miweber929]

I disagree that it was designed for higher octane. If it was designed for higher octane it would be able to take advantage of it or require it as other high compression engines do.

I guess your definition and mine differ. If there were adverse effects to using something, then it wouldn't be designed for it.

 

[icemankent]

UPDATE:
I don't know for certain (yet) - but I think I may have found the issue.
See my post in this other thread for additional background:

CBR650F - Key failure :(

So this just happened I had a lunch appointment with some friends (including my brother) about 15 mins riding from where I live. When I was about to leave, I put my key in the ignition, tried to turn it from the steering lock position to the OFF position but it wouldn't turn. Usually when this...

650f.bike

Some of you believed this metallic buzzing sound to be coming from the key/ignition.
I think you are right.

For the last 2 months my key has had issues turning in the ignition.
It would stick/jam, etc - needing to be wiggled to actually turn.
I thought it needed lube. I used dry lube. That helped, but not for very long.
Last night my bike decided that the key was no longer welcome - and it basically would not turn - no matter what.
I had to have it towed home, and then towed (the next day) to the dealer - to investigate.
The guy that picked it up did mention to me that they have already fixed 3 other bikes with the exact same issue this summer.
(They had to replace the ignition switch with a new one + kit for gas cap and seat)
I don't have their analysis/fix yet on my bike - as they only picked it up today.

Since I experienced the loud buzzing, it would be a good assumption that there's a defect in the Honda ignition.
The engine vibrations somehow resonated with the pins/etc inside the ignition - causing the loud buzzing, and eventual lock failure.
I'll know more when the dealer gives me an update - but if my hypothesis is correct - this means that any of you experiencing the same buzzy sound had better prepare yourself for an ignition switch failure in the future.
Hope you don't get stranded while out (far from home) on a ride, like I did.

I'll update the results here when I get them.

 

[thatyanguy]

UPDATE:
I don't know for certain (yet) - but I think I may have found the issue.
See my post in this other thread for additional background:

CBR650F - Key failure :(

So this just happened I had a lunch appointment with some friends (including my brother) about 15 mins riding from where I live. When I was about to leave, I put my key in the ignition, tried to turn it from the steering lock position to the OFF position but it wouldn't turn. Usually when this...

650f.bike

Some of you believed this metallic buzzing sound to be coming from the key/ignition.
I think you are right.

For the last 2 months my key has had issues turning in the ignition.
It would stick/jam, etc - needing to be wiggled to actually turn.
I thought it needed lube. I used dry lube. That helped, but not for very long.
Last night my bike decided that the key was no longer welcome - and it basically would not turn - no matter what.
I had to have it towed home, and then towed (the next day) to the dealer - to investigate.
The guy that picked it up did mention to me that they have already fixed 3 other bikes with the exact same issue this summer.
(They had to replace the ignition switch with a new one + kit for gas cap and seat)
I don't have their analysis/fix yet on my bike - as they only picked it up today.

Since I experienced the loud buzzing, it would be a good assumption that there's a defect in the Honda ignition.
The engine vibrations somehow resonated with the pins/etc inside the ignition - causing the loud buzzing, and eventual lock failure.
I'll know more when the dealer gives me an update - but if my hypothesis is correct - this means that any of you experiencing the same buzzy sound had better prepare yourself for an ignition switch failure in the future.
Hope you don't get stranded while out (far from home) on a ride, like I did.

I'll update the results here when I get them.

Well that sucks, but I'll take the silver lining indicating I'm not crazy .

Sorry to hear you had to deal with that, and I guess consider me braced. Here's hoping it doesn't progress beyond noise, but if it does it will be a good mechanical project since I've sidelined the CB650 in favour of a less ergonomically punishing ADV bike and it only goes on shorter rides these days.

For people's reference if you're wondering, my 650 has about ~16,000 KMs on it, and it's a 2019. There doesn't appear to have any progressive issues with the lock beyond the buzzing so far. I'll update this thread (provided I remember) should something more happen, but for now I'm sticking to my "pins rumbling in the ignition" theory.

 

[icemankent]

Quick update. They ordered a [new] ignition.
The old one was not repairable.
Good. I did not want to be stuck with that old ignition anyway. It left me stranded.
I'll update this after the repair is done.
It is going to be 4 weeks to get the part - so I have to wait.
[Not liking missing out on the few precious days left of riding before it gets too cold to do so !]

 

[thatyanguy]

Quick update. They ordered a [new] ignition.
The old one was not repairable.
Good. I did not want to be stuck with that old ignition anyway. It left me stranded.
I'll update this after the repair is done.
It is going to be 2 weeks to get the part - so I have to wait.
[Not liking missing out on the few precious days left of riding before it gets too cold to do so !]

Glad to hear a new part is coming in - that's good. Definitely sorry to hear about the curtailed riding soon - let this be good motivation to all off us to keep as many bikes around as possible. I once had mine gone for service for 6 weeks, and if I didn't have the other I'd have gone properly "front page of the news" nuts.

Hoping for a quick turn-around and that the weather holds up for a bit longer once you get it back!