What is this weird noise coming from my bike?

[Chicken_Satay]

My current gen Honda VFR is making this weird scraping/burping noise when the engine is off. It's intermittent i.e. only makes this noise every few minutes and it's when the engine is switched off, usually when warm but sometimes even when the bike has been sat unused for several days.

Could it be:

1. Noise from fluids cooling down?
2. An intermittent, deliberate fan that helps cool the engine (certainly doesn't sound like a fan...)?

I'm clueless, any ideas?

Here is the noise, its silent for a few seconds then kicks in (it was filmed in the dark, hence you can't see anything):

https://youtu.be/bcAQiVyqM9E

[Benni]

Some king of membrane resonating ?
Tank vent, or fuel tap, or fuel system ?

[Jazoli]

It'll be the fuel tank breather, small differences in temperature will cause the fuel to expand and it'll push air out

[Chicken_Satay]

Ok, I just used your clues to find more information on the problem via some YouTube videos. Your suggestions seem accurate and there may be a slightly blocked gas escape valve on the fuel tank lid or similar. Will investigate further now. Thanks.

[Seight_Returns]

Try opening the fuel filler after you've shut down and see if there's a noticeable vacuum/release of pressure and if it causes the noise to stop - will confirm if a blocked fuel tank vent is the culprit (which I agree sounds likely).

[Chicken_Satay]

Seight_Returns said:

Try opening the fuel filler after you've shut down and see if there's a noticeable vacuum/release of pressure and if it causes the noise to stop - will confirm if a blocked fuel tank vent is the culprit (which I agree sounds likely).

Yes, I will do this too as a very quick diagnostic approach!