Mystery noise

[Zac]

Hi,
I have been noticing a metal like sound coming from my 2018 GSX-S 750. It happens between 4,500 to 5,000 rpm in 2nd, 3rd, 4th, sometimes 5th gear. To me it sounds like a band saw cutting metal but much quieter. I removed the tool kit from under the passenger seat. Noise is still there. Any help is appreciated.

[mrstamp80]

Do you have the location identified? meaning front, middle, back?

Is your chain loose?

Does it do it in neutral? or only under a load?

Have you done a walk around and physically tightened all the bolts you can see?

Have you tried having a friend shake the bike (while it is off) and listen for anything loose?

Have you tried getting the bike up to speed and shut the kill switch off to see if you hear the noise at speed with engine off? ( in a safe place, deserted road NOT IN TRAFFIC)

One common thing that bikes experience is a loose headlight clamp / bulb. It may seem tight but will vibrate like a song when engine rpms increase. But that would be a buzzing sound more towards the front.

[Deleted]

Shit you basically summed it up

[850t5m]

My 2018 rattles or makes a weird noise as well, but I assume it's the chain. It's louder if I swing out my left leg while riding... Does yours get louder when you swing a leg open while riding?

[Zac]

I have checked just about every bolt on the bike. Couple of them needed tightened. Noise remains. Still need to check headlight assembly. It should be that or header bolt. Noise only occurs under load. If clutch is pulled in no noise. Its def not the chain. Any suggestions?

[Rosberg]

I had a strange noise on my bike.
Only under load and it increased with the revs.

Turned out to be my phone mount....😳

[Zac]

Oddly the only time the noise is heard is in 2nd, 3rd, 4th, and sometimes 5th gear. Also only at 5,000 rpm.

[mrstamp80]

Did you check your chain, clean, tighten and adjust if necessary. Chains should be checked every 500-1000k miles. Here is a video on mine, not sure if the axle nut is a different size on the 18's or not.

www.gsxs.org/thread/539/clean-adjust-chain

[Zac]

Yes the chain has been cleaned, lubed, and adjusted per the manual. I recently had it in at the dealer for the fuel pump leak recall. Mechanic I have worked with over the years on different bikes and that I trust said the noise is just natural harmonics of the engine.

[sstressfl]

Possible solution...

Check chain alignment. Do not trust a chain alignment tool.

Put it up on a rear stand, sit behind the bike, look to see if the chain is resting against one side of the sprocket or the other. Push the chain over to the other side then rotate the wheel. Watch and listen to the chain. If the pressure against the sprocket is strong, adjust the wheel alignment so the chain is not pressing hard against that side of the sprocket. Tighten. Push the chain off the side of the sprocket. Rotate. Pay attention. Listen. When its aligned correctly itll be much quieter. Smoother. And it will not press hard against either side. My bike is so smooth and quiet you can barely hear any chain noise. Also, a chain that is not aligned properly puts a lot of strain on the motor causing a lot of engine vibration.

[steve]

Sept 27, 2018 17:28:51 GMT -6 850t5m said:

My 2018 rattles or makes a weird noise as well, but I assume it's the chain. It's louder if I swing out my left leg while riding... Does yours get louder when you swing a leg open while riding?

[steve]

Please don’t take this the wrong way , it’s only stated in humor
If noise gets louder with legs open it’s either your balls rattelling or knowing how the seats are on these bikes your hemmoroids flapping