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Invisible Stebel Air Horn on a Boulevard C50

Discussion in 'Modifications and Projects' started by Blue Boule, Apr 18, 2008.

  1. I'm not really a big fan of having a visible horn on my bike as I find it interupts the look of the bike. I am however a big fan of the noise a decent horn can bring to a bike. You can see my stebel air horn on the frame just behind the front wheel in the photo below - I'd much rather that be straight frame.


    So, a week or so ago I worked out how to separate the compressor from the horn and then started working out what I would need to make it all work and where I could squeeze the smaller parts into the bike so that they couldn't be seen. Only today did I finally get the time to actually put it all together. I now have a nice new C50 with the combined horn sound of the standard horn and the stebel, and the stebl is invisible without pulling the bike apart :) In case somebody else is interested, here's how it's done. I won't cover the wiring aspect as this is covered well in other places. There's some good information with a great wiring diagram here in case you're struggling.

    Before you begin, you will need: -

    • * Some plastic tubing that's long enough to go from where you want the compressor to be to where you want the horn to be. I used some 8mm clear vinyl tubing from Bunnings and had plenty left over.
      * Two hose clamps. If you can't work out what for, I'd kindly suggest backing out of this little project...
      * Some teflon tape from my plumbing drawer to make sure the seal was nice and tight between the air horn and the next piece I used.
      * The next important piece is an air hose fitting I picked up at my local tool store. The piece I end up buying is brass, the thread fits the hole in the air horn just right so that screwing it in threads into the plastic, and the hose end is a bit smaller than my 8mm hose, but with the hose clamp it's no real problem. It looks a bit like below, though that's not the one I used as I forgot to take a photo ...


    Now, pulling the horn apart ...


    You can see the two components separated in the above two shots. The compressor on the left blows air through the outlet that has the yellow washer on it in the picture. This yellow washer causes the biggest trouble in getting the parts to separate the first time (or something it was sealed with). The compressor slides into the housing on the horn component in the second shot so that the compressor's air outlet goes into the hole in the middle of the photo below the black circular part.

    To separate the horn so you have these two parts, you need to first lever the bottom half of the compressor housing shown in the photo of the air horn as it acts as a clip to hold the compressor in place. You might want to find something to keep under there because the next bit requires some leverage. You then need something strong and thin to place under a small gap between the air outlet part of the compressor and where it goes into the horn. I used a small screw driver. It felt like it didn't want to go when I did this the first time and I was sure I was about to break it and toss $50 out the window. Alternatively, once you have the first clip levered open, you could just turn the horn up the other way and give it a hit with a rubber mallet. I tried this briefly, but once again I wasn't too keen on throwing $50 away when at that point I wasn't certain it came apart.

    The rubber seal eventually popped and the compressor came right out. I put it all back together at this point and it still worked fine. I later read reports that once the rubber seal was broken it wouldn't work anymore thus allowing air out and no noise from the horns - turns out it wasn't true in this case. Pulling it apart again later was much easier.

    Next up is simply deciding where you want the two components to go. On my C50, I placed the compressor behind the right hand panel under the seat. There's a circular housing that is probably for some outrageously expensive addition from Suzuki that I don't have. It now has a stebel air horn compressor cable tied to it. as per the photo below.


    The horn itself is on the left hand side of the bike, sitting right behind the lockable compartment. You could probably put the compressor in a similar space on the right hand side but I figured it might be more fussy about crap flicking up from the road at it, particulary the wires involved. As the horn is purely air driven, I simply made sure it was mounted in such a way that it wasn't going to get crushed once I sat on the seat and that anything coming off the tyres such as water and mud was going to hit the outside and not go straight into it. The photo below shows it in the almost final position. I had to move it from here as I felt it was too close to getting in the way of the moving frame when sitting on the bike.


    It's almost in exactly the same spot now. Just a touch lower, further to the left of the bike and angled just right so that where the noise comes out shields itself from anything coming off the tyres. To get it into this space you'll need to remove the lockable compartment completely. I had the battery compartment out too just to look around but I don't think it's required. I also had to cut off the air horn's arms that previously held the compressor but left a small part of them there so that holes could be drilled for cable ties to go through. I forgot to take a photo before putting it in and I'm not planning on pulling it out any time soon - use your imagination :wink:

    To connect them both up is simply a matter of having enough of the right length of tube. I was able to clamp the tube straight onto the compressor. The air horn needed the previously mentioned air hose fitting. I used the teflon tape around the thread and screwed it slowly into the hole. I didn't go all the way in as I didn't want to inadvertantly destroy it. Just far enough that I had a nice seal. I had the compressor wired up and working to test I had the seal by this point. On the C50, I ran the tube around the front of of the battery compartment from the horn then looped back to the compressor.

    The only other thing that might be worth mentioning is that I ran two wires from the existing horn so that both horns work. The wires run up under the fuel tank and down into the compartment shown so it's all nicely hidden. You can see the relay just in front of the compressor. It's interesting to note that the original horn goes off before the air horn and if you just tap the button, the air horn won't go off at all but the quieter horn will. I figure this is a nicer way to say 'Cya later' or 'The lights are green mate ...' without generating too much attention (or deafening your kids) Prolonged button pressing gets the full impact of course. The delay is there with our without the tubing though I expect the delay wouldn't be as obvious without the tubing.

    That's about it. Hope that helps somebody out there...
  2. I only skim read what you wrote and I couldn't get all your pics to load, but I'm sure I got the idea.

    Even when you have a decent horn I don't think its good to let everyone see it either. I too have solved many of my horn problems with plastic tubes and clamps. Getting it in nice and tight is always a problem, but wrapping it in tape is something I haven't thought of.

    I never forget to take photos btw. Silly boy.

    Some of you equipment is really unusual to me (that brass thing looks great) and I'm not the type that likes to take a horn apart, but good on you giving it a go and a little air escaping every now and then is nothing to be ashamed of.
  3. Good idea there Bouleyman.

    I'd remount that air compressor if I was you though - the instruction booklet was very clear in saying the compressor cylinder could under no circumstances be more than 25 degrees (IIRC) from vertical, and that most of their warranty claims came from people who mounted them on their side like you have...
  4. Aye I did see that in the instructions. I've not yet found another spot for it though. I could go on the opposite side to where I put the air horn but I think that would expose the terminals to who knows what coming off the wheels. I have limited options on that bike so I figured I'd give it a go there and leave the normal horn connected in case it does implode for some weird reason I don't understand :twisted: