Steibel Nautilus - Truck type...! It's big, it's very loud and I've found the best place to put it on my M1000Sie...
...Unclip the plastic horn section from your compressor body - there's a little plastic clip on the top that just bends out of the way - then prise it gently up & off. Now you have a compact compressor in one hand - which I'll mount with a relay either under the tank or down on the left side - and the trumpet section in the other. This clips straight on to the upper left fork, with a neat cable-tie or two to keep it there, and all you need to do is find an old air-hose barbed fitting, screw/glue that into the air inlet hole of the horn section, then connect that to your compressor outlet spigot with some thick-walled polyethylene tubing and a couple of small (fuel line), hose clamps to hold everything tight.
The relay wiring is simple - mine came with a standard 4-pin relay, but you can pick those up in any auto parts store. Standard Relay Wiring codes are as follows:
Relay pin # 30: 12v (fused) supply from any 'Ignition on' circuit. Fuse should be 15 Amp rating for this horn.
Relay pin # 85: Earth/ground wire (from original horn wiring).
Relay Pin # 86: Horn Switching wire (from original horn wiring).
Relay Pin # 87: Relay output to Positive terminal on new horn Compressor base.
There is one more pin, which is the earth/ground return from the Negative terminal on the new horn Compressor base - which, strangely enough, goes to a GOOD ground - preferably straight onto a 'bare metal' connection.
I havn't actually mounted my compressor yet, but will publish pics when it's all connected up and Parping at sleeping taxi drivers - I'll also see what happens if I link the original earth/ground wire from the old horn, relay pin 85 and the negative terminal on the compressor, all together.
Finally, when it's all connected up & bolted down, do check that you still have full steering travel - then you can remove the old horn and give it away or keep as a spare.
