I ordered a Fiamm disc horn that was rated at 130 dB some weeks ago. Since I ordered on Amazon.com I am well past the evaluation time so cannot return it. Not a biggie though since it was only $12 I figured it wasn't bad for the attempt. I say that cuz after I installed it I find it really doesn't seem THAT much louder than the factory horn, but it is louder. Part of the issue is that I discovered when the factory horn is on it's own circuit/wiring it is louder by itself. The Fiamm horn is a low tone horn and the factory horn is a high tone. While the Fiamm is a little louder, the discord of the two tones does make it very much more noticeable, and that is the goal. I may yet go to a local auto parts store where I recently saw another horn that might be louder. I mounted the Fiamm using the same bolt at the same mounting location as the factory horn. In fact, as the photo shows below, I simply turned the factory horn to the front and have the new horn toward the rear. I pulled the factory wire pair up under the top shelter and connected to a relay there. These wires trigger the relay when the horn button is pressed and power for both horns is directly from the battery through a 15 amp fuse and larger gauge wires so there is no attenuation due to wiring limitation. I ran the dedicated wire pair along the original wire path using the factory clamp/holders. The factory horn circuit is shared with other items on the bike and I wanted to connect it on a dedicated circuit. This works really well. In the second photo I use my orange handy knife to point out the relay (relay is black with a white base). I zip tied it to a tab on the plug stack mounting bracket there to keep it from moving around. In that photo you can also see the grounding bar in the lower left nestled in between the hoses under the top shelter. Yes, that is a standard household electrical grounding bar. That also works really well and I used that same set up on my ST1100 and the Burgman for many years with no issues. No special connectors and just dielectric grease on the contacts. On the right there is a black square block with white lettering on top. That is my Garmin GPS power converter that is connected to the front option plug ACC connectors.
The horns:
The relay and some other parts:
The relay I used has a pin 87 as well as a pin 87A. That pin 87 is powered only when the relay is "on" (only when I press the horn button and the ignition is on) and pin 87A is powered only when the relay is "off" (all other times including when the ignition is turned off). That allowed me to use one inline fuse holder for both the horns and the 12V power socket I put under the seat. The relay isolates the two items. I only plan to use that 12v socket for emergency or to inflate the tires (pump needs 15 amps) and not while underway since I have to remove the seat to use it (planned that way). I use the 12v 10 amp socket that I added in the right saddlebag to charge things while riding. This reduces how much wiring and how many inline fuse holders are finding space under the top shelter and around the battery.
The horns:
The relay and some other parts:
The relay I used has a pin 87 as well as a pin 87A. That pin 87 is powered only when the relay is "on" (only when I press the horn button and the ignition is on) and pin 87A is powered only when the relay is "off" (all other times including when the ignition is turned off). That allowed me to use one inline fuse holder for both the horns and the 12V power socket I put under the seat. The relay isolates the two items. I only plan to use that 12v socket for emergency or to inflate the tires (pump needs 15 amps) and not while underway since I have to remove the seat to use it (planned that way). I use the 12v 10 amp socket that I added in the right saddlebag to charge things while riding. This reduces how much wiring and how many inline fuse holders are finding space under the top shelter and around the battery.
