Since it's been raining forever here in NE PA I found some time to get some photos uploaded from my Stebel horn installation. I had the cowling off to do the spark plugs recently and took some photos.
The actual installation was done when I got the bike in 08.
These are just some ideas. I am a novice at wiring, and in fact I think a Stebel installation was my first wiring job years ago.
Installing a Stebel horn is a good opportunity to learn wiring, as it is simple to do- just have to buy wire, assorted connectors, and a crimping tool. I mount my relays near the battery so they are as weatherproof as possible. That way the wiring is simple to do also. I have never had a problem with a Stebel relay going bad.
I have two split Stebel installations on different bikes using the Tygon 2 fuel line, and each having about 20,000 miles on them with no problems. Tygon 2 is 1/4" ID and 3/8" OD
In general, you need to buy a few female insulated connectors to attach wires to the relay and to the horn. You need two male insulated connectors to attach wires to the stock horn wires which are pulled off of the stock horn. When I did this, I routed the stock horn wires so that the connectors that I put on are accessible from outside the bike. (just inside the frame.) They are wrapped in electrical tape and if the Stebel ever fails, I can cut the tape open, unplug the wires, and plug them back into the stock horn.
When wiring, detach your stock horn wires, mount your compressor, and your relay. Then, just attach two male connectors to two wires, and attach them to the stock horn wires. Route them to the relay, and leave them extra long. Attach 2 female connectors to two wires and attach them to the compressor. Route them back to the relay area and cut them off extra long. Then, you can work on the relay end of the connectors and the wire nut and battery connections. Two ring terminals are needed for the battery. Use 12 gauge for the positive connections between the relay and battery. If you use different color wires and write the wire connections down in a book, you can easily tell them apart and won't forget them years later.
Splitting the horn is easy by pushing up on the compressor and breaking it free of the plastic. On my first install I cut the plastic with a hacksaw, and cut slits into it with a Dremel tool to attach the trumpet to the frame.
On the V-Strom I used a mending plate to make a mount. Onto this plate I pop riveted a sandwich of a backing piece and some rubber. You can buy rubber sheeting, mending plates, etc. at your local Ace. Notice the fuel line is just press fit into the trumpet- no clamps or adapter needed, and it has never came out. When the horn operates, the tubing expands, making it too tight to blow out.
I used two U-bolts which I modified to make J-bolts, which I used to attach the trumpet to the home-made bracket.
you can see the cut-off U-bolt wrapped around the trumpet:
On the V-Strom, I attached the compressor to the down tube of the cowling stay with a grounding clamp. (right forward side) I wrapped the down tube heavily with electrical tape to get a better grip and to prevent the paint from getting worn through. This keeps the compressor vertical when the bike is upright. The grounding clamp idea came from this forum, and there are better photos of it in some other posts.
The hose is routed down through the cowling, so it is protected and invisible.
The horn is really not noticeable on the bike, and the hose is hidden by the cowling. Not one person has ever pointed at the horn and asked me "What is that thing". Compare that to the tool tube, which is noticed by just about everyone who looks at the bike.
The tube routing:
I further weatherproofed the compressor by using 90 degree angle connectors, and then raiding my spice cabinet for a plastic bottle cap that just fit over the end of the compressor tightly. I put a hole in this for routing the wires, and taped it. The wire tie keeps the hose from rubbing on the forks, and keeps it tightly up against the outlet of the compressor so it doesn't slip off.
This is a way to wire the horn easily.
This is from a different bike, but would look the same if wired as above. Notice the larger 12 gauge red wire and connector.
I put the relay next to the battery, and the relay is just hanging there by the wires unattached to anything. you have to buy a fuse holder for the 20 amp fuse, which is just a few dollars at the auto parts store.
On my V-Strom install, I had intended to use a large Posi-lock connector as my wire nut, but the wires did not all fit and I accidentally cut them too short. So I fixed this using smaller Posi-locks to connect and wire the horn the standard way. (I really like those Posi-locks).