- Jul 25, 2020
- Riding Since
- 2019
Hi Guys,
Complete newb and a bit of a mechanical idiot here, hoping someone can help me out. I've done a cursory check and don't believe anyone has posted about this on here, and I'm a bit too dense to make sense of this with the service manual. Know just enough to be dangerous but clearly not enough to fix this myself. Couple of caveats - live in an apartment building, don't exactly have a well lit / usable area to work on the bit.
Was out for a ride yesterday, noticed a strange buzzing / resonance vibration sound come in at around 5.5K RPM. Most noticeable in first gear, bit less in second, barely any in third (though I suspect that's because of general wind / environmental noise drowning it out). It's fairly high pitched, sounds like thin metal vibrating almost. I spent about 2 hours trying to figure it out and this is the information I gathered - hoping someone can comment and guide me to the right direction because it is driving me nuts.
Base information:
1) Bike is a 2019 CB650R, 5,000 kms on the odo.
2) Had it since last year, rode it last summer and now second summer of riding. Just noticed the noise yesterday, was never there before.
3) Bike isn't modded in any way, and generally doesn't get ridden hard - though I do let it rev through to redline here and there in 1st if I find a good empty stretch of road.
On the noise:
1) Doesn't seem to happen when bike is in neutral, though I do notice that the usual engine vibration is a noticeably less pronounced when it's in neutral and just standing still. My guess is that it takes less gas / consumption to get it revving up, which my affect vibration.
2) Most noticeable in 1st and 2nd gear (when riding with the visor up specifically, much less audible with visor down, can't hear it when I have my riding ear plugs in) - comes in and is most noticeable in the above range, hard to say whether it persists above due to noise from engine / wind at higher RPM.
3) It seems to be specifically linked to vibration rather than throttle position or bike speed, as it comes in when you start feeling the usual chassis vibration (standard engine vibration has always been there, no issue with that). Almost like the resonant frequency of how the bike vibrates set something off buzzing / rattling (closer to a metallic buzzing - it basically sounds like distortion? Very hard to describe, and almost impossible to capture otherwise I'd post a sound file).
4) Poking around, I've noticed some kind of a sensor or module (I believe the technical term is "doohickey") that is loose - but not so loose that I turn the nuts with my fingers. It definitely wiggles - there's metal screws (one on each side) holding it to a metal bracket, and there are some rubber / plastic washers around the plate that the module is bolted to. This is very easy to wiggle and may be the source (haven't tried tightening it yet as it's almost impossible to get in there, but I will try and borrow an extra set of needlenose pliers and tighten it a bit).
The sensor / module can be found as follows:
a) Bike is parked, steering is in the "steering lock position (fully to the left). This opens up a space in the frame.
b) Under the key hole module (so kinda under the fuel tank), in a little crevice that's behind where the front forks mount to the frame.
c) If you look at page 1-28 of the service manual, it would be behind to the left of the Headlight 8P connector (when looking at the photo) inside of the little "triangle" that's made by the frame and the mount for the front fork - except I don't actually see it labelled on the diagram.
c) If you were to get at it from the "top", you would have to at the very least pull out the fuel tank
It's light plastic in colour at the front. I know it's a rubbish description, I will try to take a better photo tomorrow (I try to minimize leaving the apartment, COVID and everything). If somehow someone actually knows what I'm talking about, I would love to hear:
1) What is this thing? Is there a reason it's loose, or should it be tightened?
2) Any other ideas about this buzzing noise, other things to check?
I've tried looking for other loose bolts, rubbing cables, etc., holding onto the instrument panel and the two "air scoops" while riding to see if they're the source of the noise, and it doesn't appear to be the case.
Any help or insight would be appreciated. I will try to update with a photo tomorrow.
Complete newb and a bit of a mechanical idiot here, hoping someone can help me out. I've done a cursory check and don't believe anyone has posted about this on here, and I'm a bit too dense to make sense of this with the service manual. Know just enough to be dangerous but clearly not enough to fix this myself. Couple of caveats - live in an apartment building, don't exactly have a well lit / usable area to work on the bit.
Was out for a ride yesterday, noticed a strange buzzing / resonance vibration sound come in at around 5.5K RPM. Most noticeable in first gear, bit less in second, barely any in third (though I suspect that's because of general wind / environmental noise drowning it out). It's fairly high pitched, sounds like thin metal vibrating almost. I spent about 2 hours trying to figure it out and this is the information I gathered - hoping someone can comment and guide me to the right direction because it is driving me nuts.
Base information:
1) Bike is a 2019 CB650R, 5,000 kms on the odo.
2) Had it since last year, rode it last summer and now second summer of riding. Just noticed the noise yesterday, was never there before.
3) Bike isn't modded in any way, and generally doesn't get ridden hard - though I do let it rev through to redline here and there in 1st if I find a good empty stretch of road.
On the noise:
1) Doesn't seem to happen when bike is in neutral, though I do notice that the usual engine vibration is a noticeably less pronounced when it's in neutral and just standing still. My guess is that it takes less gas / consumption to get it revving up, which my affect vibration.
2) Most noticeable in 1st and 2nd gear (when riding with the visor up specifically, much less audible with visor down, can't hear it when I have my riding ear plugs in) - comes in and is most noticeable in the above range, hard to say whether it persists above due to noise from engine / wind at higher RPM.
3) It seems to be specifically linked to vibration rather than throttle position or bike speed, as it comes in when you start feeling the usual chassis vibration (standard engine vibration has always been there, no issue with that). Almost like the resonant frequency of how the bike vibrates set something off buzzing / rattling (closer to a metallic buzzing - it basically sounds like distortion? Very hard to describe, and almost impossible to capture otherwise I'd post a sound file).
4) Poking around, I've noticed some kind of a sensor or module (I believe the technical term is "doohickey") that is loose - but not so loose that I turn the nuts with my fingers. It definitely wiggles - there's metal screws (one on each side) holding it to a metal bracket, and there are some rubber / plastic washers around the plate that the module is bolted to. This is very easy to wiggle and may be the source (haven't tried tightening it yet as it's almost impossible to get in there, but I will try and borrow an extra set of needlenose pliers and tighten it a bit).
The sensor / module can be found as follows:
a) Bike is parked, steering is in the "steering lock position (fully to the left). This opens up a space in the frame.
b) Under the key hole module (so kinda under the fuel tank), in a little crevice that's behind where the front forks mount to the frame.
c) If you look at page 1-28 of the service manual, it would be behind to the left of the Headlight 8P connector (when looking at the photo) inside of the little "triangle" that's made by the frame and the mount for the front fork - except I don't actually see it labelled on the diagram.
c) If you were to get at it from the "top", you would have to at the very least pull out the fuel tank
It's light plastic in colour at the front. I know it's a rubbish description, I will try to take a better photo tomorrow (I try to minimize leaving the apartment, COVID and everything). If somehow someone actually knows what I'm talking about, I would love to hear:
1) What is this thing? Is there a reason it's loose, or should it be tightened?
2) Any other ideas about this buzzing noise, other things to check?
I've tried looking for other loose bolts, rubbing cables, etc., holding onto the instrument panel and the two "air scoops" while riding to see if they're the source of the noise, and it doesn't appear to be the case.
Any help or insight would be appreciated. I will try to update with a photo tomorrow.
