I have a custom air horn now, but used a pair of Fiamms for many years, when I commuted daily. I also used a relay, as suggested already.

My claim to fame is watching a car trying to cut across several lanes on a busy multiple lane hiway, making a real menace of himself and trying to get to an exit slip road - blasting him long and loud enough that he missed the turn!

 

Hey, it's the way to go!
Now my passenger wants me to install another horn button for her so she can blast the horns if needed. Might not be a bad idea, other than the effect they might have on me! LOL
Seriously, I really like that the 2 new horns are facing forward, instead of just under the cowbell pointing down at the ground. Face it for what it is - if all you have is the stock horn, you are lacking BIG TIME. The 2 additional horns are day/night different. And, as pointed out, $25 or less, that's hard to beat!
This gives you an idea of the "Trifecta" advantage:

 

So, if I use a relay system, can I only use one relay? Have the wires for the three horns spliced together then run to a relay or do I need more than one relay?

As you must have guessed by now, I'm not all that knowledgeable when it comes to electrical systems. LOL Rather ask a question then assume the answer.

 

You can use several relays if you want, just depends on what add-ons you have in mind. On the other hand there is no reason why you shouldn't run a couple of different accessories through the same relay, which I have done myself.

The benefit of using a relay is that only a switching current, which is very small, passes through the switch by which you operate the accessory. The power to the accessory is carried by an additional wire. The wiring setup should come with the relay, simply buy a stock relay for adding an auto light, at an auto parts store.

 

What gauge wire should I use?

 

use 1 relay 10 or 12 ga wire will do fine.

you can save yourself from brain-sweat by buying an "off road lighting" wiring kit at local auto parts store.


it'll have wire ( if you don't) and a relay and an on/off switch which you won't use- you substitute your stock horn wiring to the relay where the on/off switch connects.

make sure any connection to the battery + has a fuse in line.

auto parts store or harbor freight get a crimping tool and a bunch of terminals- just get the multi-box

Mike

 

This will keep it simple and get the job done correctly.

 

Thanks for all your help. I love this forum. As soon as the horns arrive, sometime next week, Their going on. Of course living in Rhode Island, and it being winter, I won't be riding until Daytona in March.

 

I' d like to do the fiamm horns up on the tank bolts. Where's a good spot to mount the relay? I'll probably do a stock horn delete, and use that wire to activate the relay. Would like the relay to be hidden, or close to it. Suggestions?

 

I installed hi/lo Fiamms on my Classic last year and went with a relay. I could find no info on the capacity of the switch so decided that a $20 relay was cheaper than the switch assembly would be. I though about mounting them up front but went with one in the cowbell and one on the frame plate right behind the engine. It's a little close to the rear exhaust but we're not that hot up here and I don't ride in traffic. I did get caught in a backup and the plastic housing warped a bit but it still works fine. The relay is mounted under the left side cover. Great improvement for very few bucks.