So, my bike tends to get hot, really really hot. it was 113 here today. when it's this hot my fuel tank releases a sound which is somewhat like a blood curdling scream mixed with a motorized whine. I can even hear it when I'm riding over the wind and my Bassani exhaust. I've noticed if I take of the fuel cap the sound slows and stops. Almost as if the sound is the gasoline attempting to escape the tank. I have the next 4 days off so I can definitely investigate it over that time. I've also been trying to get it on video, but so far I can only get a weak version of it that doesn't keep going. Gonna probably need to already have my phone recording somehow to catch it. It is LOUD, I had a guy pull up and ask if that was my bike making that noise. It's tough describing it accurately so I'm currently searching YouTube for examples if I can find any. Anyone else experience this? or something similar?

 

Have you changed the gas cap? is it a vented gas cap?

 

It's normal, its venting.

 

It's the stock cap, doesn't seem normal to me or to the guys down at the dealership. They've only been able to catch it when it's quieter. I gonna take it out when it warms up today and see if I can get a video

 

Its pressure building up in the tank and then venting, next time it does it, open the gas cap and I'm willing to bet that it stops and you also feel the pressure. I've owned 13 bikes and they all do it, some louder than others.

 

When my bike gets very very hot , which isn't often in the UK , I get a whining , singing sound which I believe comes from the drive belt or possibly the primary . Both are correctly adjusted . The sound is most noticeable on deceleration and persists without changing note right down to very slow speeds . At least that's what I thought it was , I do have a flush fitting aftermarket gas cap . 🙄

 

Does it matter how much gas is in the tank? Louder with less gas or full? I had an issue simular but was louder with less gas. Almost like a harmonic. My tank was a touch loose. Snugged everything down and it was fine.

 

Didn't do it tonight, but rode when it was cooler. Taking it out in the morning and I'll give it a try. Be cool if that's all it is