I have the same as this, it's LOUD.......
http://www.ebay.co.uk/itm/Car-Air-Horn-12v-136db-Blast-Compact-Twin-Tone-Loud-Horns-Truck-Lorry-Boat-SUV-/160942240947?pt=UK_CarsParts_Vehicles_CarParts_SM&hash=item2578e7b4b3
How did you fit it and does it come with a relay and instructions?
It was a long time ago that it was fitted, as in 4+ years, but it's mounted hanging underneath the left infill fairing tray with the open end of the horn facing downwards.
You can see it as there's about 4cm poking down from the fairing, right between the carbs and the radiator, but it just looks like part of the bike.
I vaguely remember having to trim down some sort of bracket that was getting in the way under there as well, it can't be that important otherwise i simply wouldn't have touched it.
It will come with instructions, and if you look at the smaller photo's in the advert you'll see that all bits needed are supplied, with a relay included.
It's a ropey photo i've supplied as it's old, and i've enlarged it, but i presume the red wires on show along the frame are part of it?
This has been an invaluable piece of kit to me, and has got me out of many dodgy situations, cars
will move if they think they've just cut up a lorry, which is not far off what it sounds like. And i've made many a pedestrian do a funny dance when they've blatantly walked out in front of me without looking, especially under a train station bridge near my work where they just don't give a shit, but the horn echoes twice as loud
For the price of it i'd say give it a go, it's a lifesaver and worth every penny, and i'm sure you must know someone who could give you a hand fitting it.