gas cap whistle

[chief]

This isn't your problem but there is some useful relative info - in the mods/tips section (air and fuel) of the website btw.

http://www.vulcandrifterriders.com/gascap.html

[Scot66]

LOL! Mine does this as well....I tell my friends it's "percolating".

[Troll]

  What you are hearing is fuel vapor venting when the internal tank pressure reaches a predetermined level. The parked bike, with the engine heat boiling the fuel is generating the pressure rise. This phenomenon is called "hot soak". If you want to, you could disassemble the internal cap parts, and remove the pressure spring, but that might cause raw fuel to be expelled through the vent when the engine gets hot. Probably not a good trade off.

[jamman]

Mine does this when it's hot ... when it's cooler it does not ..

[rkmcsparky]

I have a 2005 drifter 800 and have an annoying whistle comming from the gas cap when the bike isnt running. I assume this is the fuel tank venting because as soon as I open the cap and shut it , the whistle stops for a few mins. Am I correct in my thoughts ? and is there a way to stop the whistle ? !!