The sad news is that I have read enough about
direct-replacement horns -- from Fiamm and others -- and had tried a few myself, years ago, to be thoroughly unimpressed.
If you want a
significantly louder horn, I don't think you'll be satisfied with them, I don't think this is the way to go, etc.
Over the years, I have added
air horns to assorted bikes, and have been satisfied, even pleased, with the results. It doesn't matter whether the air lines were built-in or separate -- same result. To show you that I'm not just making this up, i.e., that money talks, bullshitwalks ...
On my 2000 Valkyrie Interstate (c. 2001), underneath the bike:
View attachment 4188
Actually, sometime after that, I replaced those two air horns with a
four-electric setup that a Valk forum DIYer started marketing, and that's what you need if you really want a loud electric setup. It was a little bit louder, and mostly didn't have the maintenance issues (accumulation of road crud) that the air horns had in that location.
On my 2007 Burgman 650 (c. 2008), in the right-side cubby:
View attachment 4189
On my 2012 Victory Cross Country Tour (2012), underneath the front fairing:
View attachment 4190
On my 2008 Burgman 650 (c. 2017 -- I bought the bike used, in 2016), in the left-side cubby:
View attachment 4191
Some notes:
- All of those were in conjunction with relay-driven fuse panels I added. Those Stebel Nautilus and similar horns draw almost 20 amps, and you don't want that sort of current flowing through tiny stock buttons and switches. And you want beefy 16- or 14-gauge wires providing maximum juice to the horns.
- Even though (with the exception of the Valk) the horns were underneath bodywork, that bodywork was open to the ground, and the diminution of the horns' output was negligible.
- Even though Stebel has some specific requirements regarding the downward angle of the trumpet(s), all that's really necessary is allow them to drain, if necessary. That is, IMO such strict positioning is not necessary.
- I thought about this kind of mod to the C 400 GT, but I never got around to it. And may never. The one-piece Nautilus is pretty heavy, and when I had the dash and nearby bodywork removed for my other farkles, I was thinking that the area behind the cubbies might not be sufficiently supportive. So I passed, and it's good thing, too, what with my getting that bike replaced.
Of course, I think we all realize that evasive maneuvering is more important than horn usage, but I bet that I agree with you that sometimes it's nice to do both, to at least let a cager know that you didn't appreciate his or her actions.
Now, in terms of a
really loud horn, my favorite was a fellow Valkyrie owner -- this is a real guy, who was active on the Valk forums back in the day, and who marketed some exhaust systems to the community -- who did the loudest horn add-on that I'm aware of:
View attachment 4192
This project required a lot of work, what with an add-on tank, welding, extra plumbing and wiring, etc. You can read about it here:
Good luck with your project.
