I finished installing my Stebel Nautilus Compact air horn. I wanted the horn mounted so that it would be completely invisible. I tried many different mounting locations before I came up with what I used. I haven't seen anyone else mount theirs like this on a FZ6 so I figured I would show how I mounted mine. I wont cover the electrical portion as it is fairly generic. I incorporated my wiring into a large harness I build for my alarm, 2 12 volt sockets, gps power, 12 volt meter and special lighting.
To mount the horn hidden you must separate the horn and the compressor. They simply pull apart when you release 2 small lock tabs on the side and one at the top. The horn itself is VERY light and can be mounted anywhere, but the compressor is heavy and must be mounted almost perfectly vertical.
You will need some air hose from a hardware store, I used 3/8" x 1/4" vinyl tubing. You only need a small length of about 2 feet, or less, but it tends to come in long rolls. Next you need a 1/4" x 1/8" hose barb (one end is threaded - designed for use on pipes).
Using a 1/4" pipe tap of the same standard as the barb you are using, thread the hole into the horn. Do this very slowly while holding the horn upside down so no pieces are able to fall inside. You will need to remove the tap as you go along to clean out the little bits of plastic. You can use glue or Teflon tape to make a good seal to the barb once you are done (I used Teflon tape).
There is really only one spot under the fuel tank where you can mount the compressor upright (shown in pictures). Its a VERY tight fit. Thus you cannot use spade connectors on the bottom of the compressor for your wiring. To remedy this just drill a few holes in the bottom of the plastic lip or the compressor and run your wires though this. Then solder them in place and fill the void with a heavy duty epoxy.
I cut the air intake tube off the old bracket and epoxied it to the side of the compressor. This way you have no chance of getting water into the compressor when you wash the bike or ride in the rain, if you wanted you could run a hose to your air box to insure it doesn't suck up any bugs and kill the pump. The compressor sits on top of a heavy rubber mat that is on top of the transmission portion of the engine, so there is no risk of it shorting out or wearing through.
I fastened the compressor in place using zap straps, they just prevent a little moving around since the fit is already so tight. I had the fuel tank removed while installing this as I was installing several other items at the same time. It would be difficult to install properly without removing the tank. You may want to use a 90 degree fuel line link for the overflow hose on the side as it sits directly above the compressor. While the hose does fit and function it does slightly kink it without this adapter.