weak horn - solved!

So when I bought this bike a couple years ago the horn was shot. I bought a Fiamm AM80 and hooked it up in about 5 minutes but the thing would only work above 4000rpm! This was a huge problem because I need the horn when I'm not revving it up

So it's gone like that for almost two years until tonight, when I decided to analyze the horn on my work bench.

Turning the screw (whose silicone I was initially afraid to break) changes the current draw of the horn. I suspect it adjusts the solenoid relief space or tension of the vibrating thing.

Counterclockwise increases current draw.
Clockwise decreases it until it's open circuited.

So I turned it all the way in and pulled it out to about a 1.5-2A draw. It now works at lower voltages (12.5V) and is loud enough, though not as loud as when it drew the full 4A.

If you have problems with a new horn, it may be worth messing with the screw until you get good results. Don't be like me and put off turning a screw 2 turns for 2 years!

(edit: I also rebuilt the horn button over the winter.)

Post edited by: inline79, at: 2006/09/01 10:30

that's very interesting, and a hell of a lot easier than installing a relay controlled extra horn power circuit. Did it change the pitch of the sound when you tirned the screw?
thanks
Ricky

It changed the volume only, not the pitch by any noticeable amount. A horn relay was an option, but I'd rather have a slightly weaker horn than have up to an additional 1/10th second delay with the relay in there.

I've really got to look at mine. It's been over 2 years that I have been without a horn.

Post edited by: rstnick, at: 2006/09/03 18:49

Well I took a stab at mine again today and got her working. I used an aftermarket Fiam horn (much louder)that has one terminal and a mounting bolt, which is to be grounded. First attempt got the horn coming on as soon as I turned the key on. Due to the grounded mounting. I needed to isolate this mount (rubber mount it) away from ground. I also used the Brown wire from my front brake stop switch as the feed wire (I couldn't find the proper horn one, as my brake switch hasn't worked in ages). They both (horn and stop switch) share the Brown circuit.

Will that mean that if you use your brakes and your horn at the same time you will blow a fuse?

Will that mean that if you use your brakes and your horn at the same time you will blow a fuse?

:laugh: I hope not!

I've had the two wires/plugs from the splitter/switch disconnected for a while. Looking at the wiring diagram, I noticed the brown wire from the switch is in the same circuit as the brown wire from the horn. So I don't think there should be any problem. I better test it to be sure.