Noise from Fuel Tankgreenspun.com : LUSENET : MV Agusta F4 : One Thread
Hi, I always hear a "crying" noise from the fuel tank after I ride the bike. Is this normal. I've read in previous posts that there are some problems with fuel pressure and all. Is this related to that? Should I be concerned? Please let me know. Thanks in advance.
-- Santi Cua (firstname.lastname@example.org), November 27, 2002
Mine moans ever so softly, it is the "after glow" :)
...got a light?
-- Scot Hennon (email@example.com), November 27, 2002.
Yes it is normal. If it bothers you, just open/close the cap to release the pressure and it would be fine.
Otherwise enjoy the singing and thermal cracking as an after riding experience.
-- Yannis (firstname.lastname@example.org), November 27, 2002.
My Senna does this too. It doesn't even have to be ridden. This "sighing" seems to be caused by temperature changes, as others have suggested. If I bring the bike from outside where it's warm into a cool garage it will do this. It think it's just telling me it's happy.
-- Dave B (email@example.com), November 28, 2002.
It's just air/fumes passing through the fuel tank vent. Mostly happens when heat from the engine warms the fuel which evaporates thus raising the pressure in the tank which then needs to vent through a small airway in the fuel filler cap. The revese happens when the engine is running the falling fuel level causes a low pressure in the tank which then needs to draw in some air to equalise itself. If this didn't happen then you would have a number of problems. 1/ the tank would either blow up like a balloon or crush like a squashed coke can. 2/ the bike wont run because the vacum will beat the fuel pump and starve the engine.
It's important that this vent is not blocked - not only will your bike stop talking to you but also your bank manager (tanks cost a fortune to replace)
-- Mark (firstname.lastname@example.org), June 16, 2003.