Horn Repair?

[pete]

My horn carked it a while back and I've now had two cheap replacements that are junk.

Anyway, some searching here revealed a few posts where some guys have been able to dismantle it, clean it, and get it working again.

Problem is I can't see how to dismantle it... I took the nut off the front that lets you take the front panel off, but that's as far as I can get.

The threads I found have no detail so I'm hoping someone has some idea of a way to get it apart so I can check it out...

[rustybronco]

Is it held together by rivets? Mine all are.
I would surmise that you could open it by grinding off the rivet heads.

[mustangflyr]

My horn carked it a while back and I've now had two cheap replacements that are junk.

Anyway, some searching here revealed a few posts where some guys have been able to dismantle it, clean it, and get it working again.

Problem is I can't see how to dismantle it... I took the nut off the front that lets you take the front panel off, but that's as far as I can get.

The threads I found have no detail so I'm hoping someone has some idea of a way to get it apart so I can check it out...

Had one of mine quit so I used a small pair of channel locks pried back the crimp and opened it up. It had gotten wet so the rust stopped it from working. After using my bead blaster back to rust free sprayed it with WD-40 and put it back together. Used a hammer and dolly to crimp and voila it works, don't forget to use some sealant around the horn before you crimp it. Looks and works fine.

[pete]

Cheers for the replies guys... Dale, no rivets on this, just the nut and what looks like a seam.

Mustangflyr, thanks that sounds like the method I'll need to use.

I did see what looked like a seam, so I'll give that a go.

The 450's being serviced this weekend, so while I'm doing that I can hopefully give the horn repair a go too.

[Matchless]

Pete,
I have two off an Opel Corsa car, hi and lo frequency and they work very well and not too big. Bosch made.

[pete]

Good to know Andre. I've had a quick look around locally and there's not a lot available, but it was only a quick look... if I can't fix the stock one I'll start the hunt again.

[pete]

Ok so I managed to dismantle it last night and it is nice and clean inside. No rust, no crud, just clean.

Tonight I started figuring out how it works and I sort of get it... but I'm a little lost as to how to put it back together in such a way that it works properly.

If I remove the little adjustment screw on the back, it buzzes... not a beep though, but a buzz.

If I screw the screw in, it stops altogether, but at least now I know the reason why it stops!

I measured the impedance across the terminals, and I saw about 2 ohms, which makes me think the coil is ok.

So here's what I see...

Very clean inside:



The bar there has another piece of metal below it that presses those contacts together (piece of metal and contacts circled in red). Press the piece of metal down to open the contacts and the impedance of the coil goes open circuit.



The centre bit here sits in the centre of the coil and the coil turning on causes it to pull down, opening the contacts above. This turns the coil off, releasing the centre bit which closes the contacts and starts the cycle again.



So that's how it should work... however...

If I screw the little adjustment screw on the back in, it pushes the metal bar up (circled in green in the photo of the contacts etc. above).

When i then put the centre bit with the front disc on in and hold it down, it presses down on the piece of metal that then opens the contacts... and of course then the coil doesn't turn on and it does nothing.

If I leave the adjustment screw out, it buzzes like it should work, but not high enough frequency to actually beep.

So, with that really crap explanation... anyone have any idea how this should work? I must be missing something really obvious...

[razor02097]

Pete. The only thing you can really do is to use a small piece of fine sand paper and fold it so the sanding surface is on both sides then place it between the contacts and pull so the contacts are cleaned off. Then reassemble.

The horn will not work unless the spring steel diaphragm is sandwiched really tight on the body of the horn with the crimp ring. If you have buzzing while it's apart that is a good sign.


I tried adjusting the screw on the horn and the horn worked but was unreliable. I ended up getting a high and low tone horn from oreilly's then using a relay hooked it up to my existing system. here is the post

http://www.thegsresources.com/_forum/showpost.php?p=1689167&postcount=208

I have to say having the high and low on a relay makes a gigantic difference! Plus the way I have it wired I didn't modify anything. I have the relay powered from the stock circuit then added a circuit from the battery with an inline fuse. About an hour and I can unbolt the modded horn and bolt the stock back on.

[Matchless]

Pete,
The diaphragm is what causes the loud sound, like those old record players. Or nearly like a speaker

The screw is to adjust the internal solenoid contact, which determines the movement distance of the diaphram and in short the sound you want. The solenoid is connected to to the diaphragm, it pulls diaphragm in when powered, contact opens and removes power, solenoid operates again repeating this continually while the horn is powered.

When all is together and you adjust the screw carefully until it starts buzzing, then with careful adjustment find the sweet spot where it hits the resonance frequency. Lock the screw and recheck, as the adjustment is quite sensitive and even locking the nut may move it off the resonance point.

As razor02907 says, using double horns with hi and lo makes an big difference, instead of the squawk one horn makes it will sound like a big vehicle!

[pete]

Cheers guys.

I didn't get back in the garage tonight but I think what I'll do is get it back together after sanding the contacts a little to be sure they're clean, then get it back on the bike as a stop gap.

Even just a buzzing is more than the cheapy horn does

Once I've done that I'll try to get a refund on the cheapy horn... not a lot of $$$ but annoyed that two have died the same way so soon and they're obviously crap and the shop needs to know it.

For a permanent solution I'm eyeing off these pairs of horns on eBay as I can't see anything similar locally at the moment:

http://www.ebay.com.au/itm/Italian-LEB-80MM-Compact-Red-Cap-Car-Motorcycle-4WD-Horns-T80-2R-12-Stebel-/120977180923?pt=AU_Car_Parts_Accessories&hash=item1c2acd48fb&_uhb=1

http://www.ebay.com.au/itm/STEBEL-ELECTRIC-TWIN-HORNS-HI-LOW-COMPACT-NEW-FOR-CAR-TRUCK-12V-12-VOLT-TM80-2/300941033853?rt=nc&_trksid=p2047675.m1851&_trkparms=aid%3D222002%26algo%3DSIC.FIT%26ao%3D1%26asc%3D261%26meid%3D862301387554275137%26pid%3D100005%26prg%3D1088%26rk%3D1%26rkt%3D5%26sd%3D120977180923%26

[rustybronco]

http://www.ebay.com.au/itm/Wolo-Bad-Boy-Car-Bike-12-volt-Compact-Air-Horn-Wiring-Harness-Relay-Kit-Loud-/400379290652?pt=AU_Car_Parts_Accessories&hash=item5d3877241c

http://www.ebay.com.au/itm/Stebel-Nautilus-Compact-12volt-Car-Air-4x4-Horn-Black-139dB-Loud-Bike-Motorcycle-/130967138050?pt=AU_Car_Parts_Accessories&hash=item1e7e3fef02

[pete]

Cheers Dale... 18 amps for the bad boy though

I think the 5.5 amps each of the electric Stebel could be the way to go, although the bad boy or air Stebel's noise levels are tempting...

[rustybronco]

Cheers Dale... 18 amps for the bad boy though

You wouldn't need to hold down the horn button the entire time you're riding.

[razor02097]

You wouldn't need to hold down the horn button the entire time you're riding.

This


All you need is a good blast when you require it's use. If you are going to go aftermarket you will most likely need a relay anyway.

[pete]

Yes that's very true... I'm just thinking of re-using the wiring setup I have for my aux power socket but if I don't use that then it won't be a problem (thin wire).

I stuck the original one back together last night, clamped the front on as tight as I could, stuck it on the bike and it made a brief sound somewhat resembling what may be a beep... it was too late to test it properly so I will give it a good test this morning when I'm on my way to work.

I'm hoping I can get a refund for the cheapy horn then find a proper replacement... that bad boy is looking good I reckon!