2020 Ducati V4S Gurgling Sound

So, I finish my ride, bring the bike back home and park it in my garage. No drama, right? Yet...each time, when I go back out to the garage, often even after 30 minutes to an hour, there's a strange gurgling sound coming from my bike (like the gasoline is gurgling and dripping somewhere) and the garage is smelling of gasoline. I don't see any gasoline leaks. What gives?

Tank nearly empty. Fuel boiling from heat of engine under tank.

I see. So nothing to be concerned about?

Not usually, alot of bikes do that after a ride. Pressure in gas tank purging

randomwalker said:

I see. So nothing to be concerned about?

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For fuel to reach boiling point the heat would need to be around 200 °C (395 °F), I find your assumption both unbelievable and extremely dangerous. I would probably lean towards the radiator reservoir tank. Could also be a defective thermostat.

After I removed the evap canister, no more gurgling noises. The fuel is not boiling....

After a ride, fuel pressure inside tank is equalizing with ambient atmospheric pressure outside, via valve/vent within fuel cap. Ducatis have done this for as long as I can remember. If you smell gas that is something different however. Is the smell noticeable from afar or when you are stood next to the bike?

razz said:

Tank nearly empty. Fuel boiling from heat of engine under tank.

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Fuel boiling? Physics and/or chemistry not your strong point then?

Written without thinking! :-(

razz said:

Written without thinking! :-(

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hahaha you just forgot to say “sounds like” it’s boiling

You fuel is expanding after being warmed up by the heat from the engine and the fuel overflows due to a natural phenomenon defined as thermal expansion. As the gasoline heats up, it's volume will increase in proportion to the increase in temperature. The same thing will happen with the fuel tank itself, but for solids the volumetric expansion coefficient is much lower in comparison to the expansion coefficient of a liquid. As such, if the tank is filled to the top with fuel, and it heats up, it is most probable that the fuel will expand and overflow from the tank. If opening the fuel cap stops it, then that is the culprit. It may be your overflow tube is kinked (bottom of lower fairing- look for fuel/ the smell of fuel after your ride) and that may be the source of the sound. But i agree it's not "boiling", LOL. One piece of advice- try not topping of the tank when refueling- maybe 5mm below the lip of the tank opening.

Chemical engineer here. I’m not saying that his fuel is boiling here. It probably isn’t, but gasoline starts to boils much lower than 395 F. The 395 F is it’s final boiling point. It has what’s called a boiling curve because it isn’t a single molecule. Look up gasoline initial boiling point.

I had my tank emptied and repainted, after reinstall and after first ride it was doing exactly that. For a long long time. Maybe an hour. I never had it do it again before or after. I think it is a non issue, unless it keep repeating. The only way I found to get rid gasoline smell in the garage , particularly in hot weather and with tank full is to route the hose through the fairing, otherwise the way stock Ducati lower fairings made with those plastic attachments where hose connects , some fuel will be collecting in the ‘pan’ and it will stink. This is much worse if you run race exhaust and like wheelies. Cheers