I had the same problem with my bob, believe or not they just had to tighten the horn mount. it had vibrated itself loose. problem solved

 

The stock horn on my bike sounds like a friggin train horn when I hit it. It's almost embarrassing it's so loud.

As far as taking it to the dealer to fix it, I wouldn't do that..doesn't seem to be that critical to have their grubby hands all over it at whatever outrageous cost it might be. Take the horn cover off and check for loose or frayed wires. If it works "sometimes" it's got to be something loose.

 

Weak horn? Get louder pipes.

I actually get embarrased when I hit the button that activates that queer sounding horn.

Sounds like a dying goat or something similar.

 

My horn sounded exactly the same...and if the bike wasn't running (just aux power) forget it..."muffled goose". I took it back and they replaced it without question.

Todd