xs400

I have been working on a neglected xs400. Finally got it to start after working on the points and swapping out the original carbs(filthy and chewed pilot screws) for clean carbs. Everything now works except the horn. Multimeter shows power from the hot wire and ohm reading when the horn button is pushed on the ground wire, no noise from horn or the new one I bought. Everything on the switch works but the horn. Any suggestions?

 

I would say bad ground or other connection somewhere, Make sure the horn works hook to wires to battery and jump to horn, May sound dumb but I've had it happen before.

Some horns draw alot of power and won't work on bikes, I know on my 77 goldwing, the horn won't work unless the bikes running, or else there just isn't enough power there, I've tracked all the wires tried two different horns from ebay, and all the same.

 

Your horn should have two terminals on it, and the horn button on the handlebar switches to ground, i.e. battery --> horn --> horn button --> ground.

If you test with a voltmeter, you should have voltage on both wires at the horn, and on one side of the horn button. If you have no voltage at the horn on either wire, you have a bad fuse/connection/wire. If you have voltage on only one side of the horn terminals, then you have a bad horn. If you have voltage at the horn and at the horn button, but it won't work when depressed, then you have either a bad button or a bad ground. Solve that last problem and you'll be good to go. (Keep in mind that I'm assuming that you don't have an aftermarket horn relay and duel horn set up or some other configuration that I can't see from here. :wink: )