horn "defibrillation"

[willxs650]

Hello All, I'm new to the site but today I made a simple small repair and thought I'd share it since I've been reading so many great tips here. (I thought I already had a lot to do on the bike until I started to read the Tech section!)

In any case, the horn on my '78 xs650e stopped working few months ago. i thought i wouldn't miss it but riding around in street traffic there have been times i really wish i had it, so today I finally got some time to take a look.

First I checked the voltage going into the horn and was happy to find about 12 volts between the two wires (brown and pink) going into the horn when I pressed the horn button. So I figured the horn must've died.

So I took it off the frame and cleaned up the contacts and connected it to a tickle battery charger that puts out 14.5 volts. The horn made no sound. Then I figure the thing can't be that complicated. There's some rust and tarnish on the outside so I figured the inside must be similar too. Maybe whatever's making the sound inside is rusty too? So I knocked on it semi-gently with the back of a screw driver, and also dropped it on the table a few times to see if I can shake something loose inside. Then I hooked it back up to the trickle charger, thinking that a slightly higher voltage would help to convince it to work. And that it did! A little timid at first but after few tries it made a loud, buzzer sound.

Then I hooked it back up to the bike battery and it made the same sound it used to. Compared to my previous bikes I would say the xs650's horn is the loudest which's great in traffic, so I'm very happy to see it back alive again.

here're a couple of before and after videos of the repair:

before (the "defibrillation"):

after:

will

 

[pregrid]

You got a license to practice medicine on a motorcycle? I'm reporting you to the AMA (American Motorcycle Association) if you don't.


Good job, just saved yourself $29.95! It all adds up.

 

[xjwmx]

It's a good start but you can't join this club unless you take it completely apart and use dental picks and home made tools on the crud and possibly boil it in Pine Sol.

 

[angus67]

mine sounds like that too!!!
So your sayin is all i have to do is rap it on a table a few times?

 

[jayel]

mine sounds like that too!!!
So your sayin is all i have to do is rap it on a table a few times?

think goat horns just bleat don't they? I have taken horns apart before, like opening a speedometer or tach pretty simple inside just a contact relay, clean the points and any rust out

 

[willxs650]

haha no medical license! but i did have some whiskey for the doctor in case the patient doesn't make it.

i totally wanted to take the horn apart but all the bolts around the horn (if that's what they are) are all rusted and wouldn't budge. i was ready to order a new one but figured i pass a little current through it and rattle it a bit to see if i can shake anything up.

angus67: i rapped the horn a few times with the back of a screwdriver. then hooked it up to a trickle charger. but i was just trying to get it to work at all. if yours already is making a sound then i'm not sure if rapping it would change it much. but maybe if you take it apart with jayel did and clean the insides maybe it'll change the sound?

btw, that horn must weigh a pound at least! maybe more. it almost seems to be made out of cast iron.