Stebel Nautilus Air Horn Install w/pictures and comments
I installed the air horn in the same place as the original. First I split the horn in two, just pry the metal air pump away from the plastic horn housing with brute force.
I never took a picture of mine, so here are pics I stole from elsewhere once I realized the need. Mine looks pretty much like these, except I used different hosing and a different nipple for the air horn. Regardless, you get the idea. Split the puppy in two, get some hosing, and find something to stick in the intake hole of the plastic horn so that you can mate up the hose.
Here is the air pump (compressor).
Here is the plastic horn. Mine looks a little different. You can see where they inserted a nipple into the hole to accept the air hose. I used a brass fitting and epoxy. They used some cheap plastic jobber.
Here is the mounted air horn mounted in the OEM position, in a downward position as recommended, and facing out toward the soon to be bleeding ears of that woman putting on lipstick in rush-hour traffic.
I fashioned a one inch extension with a strip of metal for each side to extend the plastic chrome horn cover OUT by about 3/4 of an inch. Perfection is not necessary, it almost fit without the extension, but needed about another 1/4 of an inch, so I just used the extenders instead of forcing it.
Here you can see the 1/4" inside diameter fuel hose that I used going into the air horn. I used a 1/4" inch hose nipple and secured it with epoxy, then slipped the hose over it, and used the small hose clamp that you can see to secure it.
I then ran the 1/4" hose under the headlights and then through the plastic wire cover on the LH side of the bike just under the gas tank, and slipped it back up into where the wiring harness is on top of the engine.
Here is where I mounted the pump. There is conveniently a hole in the frame, then I stole the OEM horn bracket/brace with which to extend the horn down further. I had it directly on the hole, but wasn't sure if it would clear the tank ... it was pretty close. My tank is in a different state getting painted, so I couldn't check the fit, and just moved it down further instead. You can see the 1/4" hose coming from the plastic cover and into the air pump. Easy enough.
Obviously you can mount the pump anywhere. I had it initially hooked up with about 10 feet of hosing, and it performed the same. Once I found a home for it, I cut the hose back to accommodate my location. I was considering placing it in the old air box, but this seemed like a cool place instead.
Now for the wiring. I neglected to purchase the wiring kit ... so I got no instructions or wires or anything. I did find a wiring diagram online, and the horn luckily came with the relay, which I obviously used.
Black from the negative terminal on the air pump goes directly to the battery, which is about 12" away. You could also run it to the frame, but the battery was easier for me.
Red from the positive terminal on the air pump goes to the rely post marked "30." I purchased the little female "B" shielded wiring clips to make everything go together nicely.
Next, I pulled the OEM horn wiring all the way back from the horn mount, through the plastic wiring cover on the RH side, and over the engine. Then I used male "B" shielded wiring clips and just plugged in a wire to each. I ran the extended OEM horn wires to the relay at posts "85" and "86." I do not know if there is a difference or if it matters which goes where, but I ran the OEM clip with two wires behind it (extended by my wire) to the relay at post "86" and the OEM clip with just one wire behind it to the relay at post "85."
Here you can see where I mounted the relay, and all the connections. The only remaining connection to make is the wire directly from the positive terminal. I got an inline fuse, and put in a 30A fuse. I wired one end DIRECTLY to the positive post of the battery. I actually spliced it into the positive battery harness to make it look nice. You can see the splice, and the fuse holder, and then the other end goes into the relay at post "87."
That's it. The project was made somewhat more convenient by the fact that my bike has all of the tins removed, but I think you'll just need to lift the tank, remove the RH side panel, and remove the seat. From there, you should have access to everything you need.