I have a 07 Rincon. There is a noise coming from the vent tube on the fuel cap. Seems like a fuel pressure problem. When I crack the fuel cap it stops. Is there any sort of fix or solution? My 03 Rincon does not have this problem. I have tried a different cap, but same problem.

 

Maybe it's because your 2007 is fuel injected and the 2003 is not??

 

It can make a kind of perculating sound, usually when the engine is hot.

I think it's just the fuel vapor making its way through whatever condensed in the tube.