Let's face it - you shouldn't need the horn. But when you do, it makes sense to have something which is as loud as possible!
A while ago I had decided that I would install a Stebel horn to replace the stock item.
The model I decided on is the electromagnetic Stebel Nautilus Compact. It's seriously loud, at around 139dB.
WARNING: You may wish to turn your speaker volume down....
The biggest problem is not, as you may think, the wiring. It is simply where to fit the thing. It's a fairly large piece of kit (as the actress said to the bishop). Whilst I was doing the swing-arm maintenance I decided to take advantage of the fact that the side panels and seat had already been removed, in order to install the new acquisition.
I tried various locations, even removing the crash bar covers to see if the horn would fit. Now, it is possible to separate the Stebel into its two main components; the horn, and the air compressor - if this is done, then the compressor can be fitted in the tail section of the bike, with a rubber tube running to the front where the horn is mounted. I decided to try and install it in one piece if at all possible. Even on the Pan, this proved difficult.
I eventually found that it would fit nicely inside the left-hand fairing, cable-tied to the fairing support bar.
Removing the stock horn was fairly easy; it's only held in place by one bolt. I carefully disconnected the electrical connections as I was going to re-use these for the Stebel (I had also considered connecting the Stebel in addition to the stock horn, with a switch to select which one to use, but at the end of the day I decided to keep it simple.)
Following various recommendations I'd read regarding the relay which comes with the Stebel, I discarded it in favour of a 40-amp relay. I already had a spare wire running from the rear auxiliary fuse box to the front of the bike, so I installed a 25A fuse, and connected the front of the wire to the terminal marked "30" on the relay.
The light green wire which fed the old horn was reconnected to terminal "86" on the relay.
I then connected the darker green wire to terminal "85" (this is earth).
The final terminal marked "87" was wired to the positive terminal of the Stebel.
Lastly I connected a new earth wire from the negative terminal of the Stebel to a bolt on the frame.
I cable-tied the relay to the fairing support bar above the Stebel.
Putting in my earplugs, I switched on and pressed the button.
I knew that the installation had been a success when my wife poked her head out of the front door to see what all the noise was about.
This thing is LOUD.
Want one? You can get one here.
