Any luck repairing horns?

Given the situation some of us are in, trying to find obsolete parts, I'm wondering if anyone has tried drilling out the rivets on a moped horn, dismantling it, cleaning it, and then riveting it back together? If these were available at WalMart for $5, then the answer would be obvious! I have a 77 Smily that hasn't been on the road since 94 or so. It's been down cellar collecting dust. it's getting a new plate tomorrow, and will actually get used as a pleasant diversion from my '77 CB750, but the horn only works once in a while, and then only a meek little rattle. I'd be willing to take this one apart & fix it, if anyone could give me some ideas. Thanks.

Re: Any luck repairing horns?

Ron Brown /


Your name says it all, you could be even cheaper than me! : )

Yes, fixing a horn is relatively easy. All it has inside is an electo-magnet which pulls on a diaphragm. The diaphragm has a conyact point on it which opens the circuit to the coil and allows the diaphragm to return and close the contact....

Before you dis-assemble the horn, connect it to a battery of the correct voltage, 6 or 12, and see if excersizing it helps, sometimes this will clean the points and restore the horn to it's original "AFLAC Duck" glory.

Also, examine the outside of the horn carefully, look for a screw with a lock nut or thread locker on it. If you find one, this is an adjustment for the contact point gap. You can often restore the horn by adjusting this screw.

If you have to dis-assemble it, figure out how the point gap is adjusted, then clean the points and re-assemble it with screws and nuts for testing. You may have to do this a couple of times to get an acceptable tone. Then you can pop rivet it if you want.

Keep in mind that a horn draws a lot of current with the points closed so don't leave it connected too long if it is not honking correctly.

Go for it,


Re: Any luck repairing horns?

SteelToad /

I've tried this a few times with old car horns..

Go to the pharmacy and get a bottle of 91% rubbing alchahol and just pour it on in

to the horn (which should be disconnected at this point). fill it about half way if it

holds fluid, and shake the hell out of it. Sometimes it's enough to wash off any

loose dust and grime without having to take it apart. Use the 91% because the

regular stuff has more water disolved into it, and putting water on metal or electrical

circuits is generally a bad idea.

Re: Any luck repairing horns?

Ron Brown /

This may be some help to a horn with a "horn" on the front but ped horns are just a diaphragm with a grille in front of it. If they are in good shape, they should be waterproof and impossible to get liquid into.


Got it!

I ground off the rivets, took the diaphram out, and I think I found the problem. The diaphram, which was a round steel disc, had wear marks where it had contacted the electromagnet. I sanded it with 320 wet-or-dry, riveted it back together, and now it sounds at least like the AFLAC duck when he's extremely hung over. Thanks for the advice..... it only took a half hour or so, and saved me hunting for a 24 year old moped horn!


Re: Don't do it!! (Again)

I've used this title before when some one asked about cleaning a muffler with muriatic acid....


Moped horns work on AC voltage which uses the alternation of the currrent to make the diaphragm vibrate. A DC horn uses and electromagnetic coil and a make and break switch (points) to make noise.

DC current will burn out the coil of the AC horn.


Re: Got it!

Ron Brown /


Re: Don't do it!! (Again)

Ron Brown /


Thanks, I should have noticed that (administers dope slap). That also explains the absence of an adjusting screw and why Scott does not mention any contact points.

Strange that you can work on something for ever and the obvious does not sink in!


Re: That's how we learn

I made that mistake once, then found a horn someone had done the same to.

I just want people not to learn the hard (expensive) way. And I learn alot of good stuff here too!


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