Stebel Nautilus Horn

This describes the steps I used when installing the Stebel Nautilus Air horn. This unit puts out 139db at 4" from the horn. Believe me; it is very loud!

These steps are for installing on a 2004 Kawasaki Vulcan Mean Streak but may work for other years and models of Vulcans.

Materials

10" wide stair riser bracket (Home Depot)
Two 6mm allen-head bolts, lock-nuts, and flat washers
5/16"id vinyl hose (about 1')
5/16" to 5/16" vacuum connector
2 1/4" hose clamp
14ga wire (about 10')
20-amp inline fuse
Four female blade connectors
Two nylon ties -- your choice of color

Preparing the Horn

Separating the horn from the compressor as seen in images #1 thru #5. Image #6 shows how the compressor is to be connected to the horn via the vinyl hose and the vacuum fitting.

Modifying the Horn

Images #7 thru #11 show how the bracket on the horn must be cut back so that it can be mounted on the down tube of the frame using zip ties. I just used a dremel cutting wheel to remove the extra plastic from the bracket.

NOTE: Be very careful when cutting the bracket that you don't accidentally slice into the diaphragms on either side. If you puncture the diaphragm case it will present an air leak and reduce the sound or even make the horn unusable.

Compressor Bracket

Images #15 thru 17 show how the bracket location was determined and how the bracket was modified in order to mount it in place using the existing mounting holes at the bottom of the frame down tubes. Two holes were drilled for the 6mm bolts that mount the bracket to the frame and portions of the bracket were removed (image #16) to provide adequate clearance. Note that the riser bracket is very hard steel and you will need patience and a sharp blade to get through it.

Note, too, the orientation of the compressor shown in image #17: base to the outside, towards the horn and the body rotated so that the original mounting boss on the body of the compressor is angled back away from the radiator connections. This also places the air intake hole facing the bend in the bracket, in a fairly protected position.

Also, there is a ring that surrounds the head of the compressor and keeps the compressor body out and away from the bracket. To keep the compressor body parallel to the bracket, I added a small 6mm bolt through one hole in the bracket to act as a spacer between the body of the compressor and the bracket. When the hose clamp is tightened, the head of the bolt keeps the compressor body parallel to the bracket and keeps it from pressing against the frame.

Wiring

Images #19 and #20 show the wiring connections at the compressor and the relay. I just ran a wire from the relay (image #20) directly back to the postive battery post, routing the wire along the left upper frame member using the existing hose/cable looms. Image #19 shows how I connected the negative of the compressor directly to the frame ground using one of the bracket mounting bolts. I connected the positive of the compressor to the relay via a line that has a 20-amp inline fuse. It was convenient to simply mount the relay where the stock horn was located since the horn connections were present there.