Modern Vespa

Ok, so I was finally embarrassed enough of the little "beep beep" to get a real horn. This is a safety issue. I was almost run off the road the other day as 70mph because the jackass couldn't hear my horn.

There are some really good threads on this topic but they lacked a couple of pieces to the puzzle that made it more difficult for me then I think it should have been. Hopefully this will clarify a few things.

First off, dougl65's post was a real help:

Installing a Stebel Nautilus Compact on an MP3

Followed closely by Lex500's post which has excellent placement pics for the MP3 500 and a great bracket diagram that I used in my install.

MP3 500 Stebel Horn Install Instructions

Where I found these threads lacking was in more specifics for the wiring and the !@#$%^% annoying "U" shaped panel that required removal to deal with the old horn. Other than that they are spot on.

So first off the wiring. Some threads have indicated that using the old wiring will fry the wires. This is only true if you try to use them to power the horn. But if you only wire them into the relay as a form of "activation wiring" then they are fine since the relay draws power directly from the battery wires you should run. Use at least 14 gauge wire (smaller gauge is thicker, thicker can handle more power) and install a inline fuse (available at any Radio Shack). The wiring setup in dougl65's post is exactly what you want. It's safe and effective.

Now for the hard part. To get to the stock horn you need to remove the "U" shaped panel that separates the engine compartment from the front wheels. This involves 12 screws of 3 varieties. Remove in any order, but make sure you keep track of them. I always grab a scrap piece of cardboard, draw out the piece and shove the screws into a relative space on the diagram.

Now put your bike up on the center stand, then release the suspension lock. Trust me on this is helps a great deal as you need as much space as you can get. Now work out the panel slowly and carefully. it's difficult but will eventually "pop" out.

I then removed the stock horn (trash) and plugged in the old wires into the appropriate posts of the Stebel relay. I then zip tied the relay inside the left panel where there is a "blank" holder for the fuse box that can be seen under the right foot panel.

Then I ran a 14g wire directly to the battery, with an inline 20A blade fuse. And a 14g wire to the positive post of the horn. And used a 14g to ground the horn on the frame.

Now to snap it all back together...especially the "U" panel. Ok the trick to this is to point the front wheels straight forward then push the U panel up into its general area. Now you will need to pop the plastic "downtube" that covers some of the frame back into it place. Once you do this the rest of the U panel will slide into place. If you try to push the U panel back into place and then try to snap the downtube plastic into place...well I hope you have a full head of hair because you'll be pulling it out. Hopefully the pics below will help you visualize this.

Man... I am even more jealous of your mp3 now.

Nice! and thanks for the great write up.

Schlagle, great post. How long did the total install take? I installed the Givi windsvreen this afternoon and it took me an hour and a half, but I finally figured everything out.

I want a louder horn, but when it comes to the wiring, I get scared and I am very intimated.

BTW, where did you get that awesome cup holder? I need one!!!

If you leave the original horn in place and can get to its wires through the left foot panel then the job is substantially easier. I'm not sure if this can be done though. I'm hoping someone can pop that little panel off and take a look. It's only 1 screw, but knowing what you are looking for in there could be difficult.

I spent 6 hours doing mine but that includes rewiring my 12v outlet and digging around through as much of the wiring as I could. I'm trying to track down a short somewhere. That's why I had the rear panel off. It's not necessary to do this install.

The cup holder can be found in the link below. And it is awesome. I love it. You can mount it solid or so its swivels, and even change it back and forth to suit your needs. It barely touches my right knee if I do a very tight low speed turn.

http://www.kuryakyn.com/products.asp?bn=All&ci=3801

That's how I did mine - the horn wires can be accessed from the side left panel. Just cut them as near to the horn as possible and then there's loads to play with while wiring up the relay.

Schlagle thank you very much