Sorry to bump an old thread...but did anyone figure out what causes this sound? My 2007 Custom also makes this sound :/

 

I read another thread where a similar sound was traced to some kind of pinhole leak that was causing the fuel pump to work overtime pretty much all the time trying to keep pressure in the tank.

I can't know if its the same sound because the other thread didn't have a video.

Mine doesn't do this, but I'll keep an eye out for it.

If someone asked me to guess: It sounds like the fuel pump. That is where I would look first. Probably good to drain it, remove the tank completely, clean it out, check the lines, check the petcock, etc... and either replace the fuel pump or at least have it checked (if that is possible).

 

Thanks for replying. If I told you this only happens when I leave my bike in the sun for a while would you still think it's the fuel pump? I'm no bike expert, so I don't know why the higher temperature of my bike would cause this. If anything the higher pressure in the tank caused by the sunlight would mean the pump has to work less hard.

 

Have you tried leaving it in the sun until the tank heats up, and then opening the gas cap to vent the extra pressure before you crank it over?

Give that a shot and see if it changes the behavior. Maybe the vent for your tank is blocked or something strange like that.