Beavis and Butthead Get a Motorcycle Electronics Lesson

I’m in the midst of “upgrading” my wimpy little stock horn to a pair of automotive-style horns :smiling_imp: I initially put them in series and they seem to work fine that way, but others suggested a relay would make for the best installation. I assume that the relay I bought follows standard wiring color codes, but just wanted to make sure before I start hacking and cutting. Any link to a schematic or other advice welcome.
EDIT: a pm from one of you tech guys would be fine.

Red=(+) in
Black=(-) in
Yellow=switch in
white=(+) out to horns

I presume the ground to the horns should be a frame point close to the horns, correct? I’m not familiar with the motorcycle term, but I’m planning to put them in the location that would correspond to the down tube on a bicycle.
Cheers, -Sal

The circumcision thread’s over here: forumosa.com/taiwan/viewtopic.ph … 3&start=50

HG

[quote=“Huang Guang Chen”]The circumcision thread’s over here: forumosa.com/taiwan/viewtopic.ph … 3&start=50

HG[/quote]

oh dear, I guess the moishe’s knife slipped… how embarrassing. Anyone have a band-aid?

he missed and got the sack.

maybe you should connect some relevant pieces to the relay when it is still off the bike and has long wires, just to test it out.

[quote=“Salvatore Armani”]I’m in the midst of “upgrading” my wimpy little stock horn to a pair of automotive-style horns :smiling_imp: I initially put them in series and they seem to work fine that way, but others suggested a relay would make for the best installation. I assume that the relay I bought follows standard wiring color codes, but just wanted to make sure before I start hacking and cutting. Any link to a schematic or other advice welcome.
EDIT: a pm from one of you tech guys would be fine.

Red=(+) in
Black=(-) in
Yellow=switch in
white=(+) out to horns[/quote]
Not sure if those colors are standard, except the + and -. But what do you mean by ‘in’ related to the + and -?

The relay should have 4 connections, two for the relay coil (let’s call it a and b) and two for the switch inside the relay (c and d). Horn has e (+) and f (-) connectors.

Then wire:
From + of the battery to the switch input. Output of the switch to a of the relay. b of the relay to -. Now the relay should click if you flick the switch.
From + of the battery to c of the relay. d to e of the horn(s) and f to minus.

It’s probably a good idea to insert a fuse between the battery (+) and the switch, and between the battery (+) and the wire going to the relay connector a. I installed a horn in my car once for the alarm system and the wire went up in smoked when the alarm was accidently triggered as the wire to the horn touched the chassis and there was no fuse inbetween.

BTW: I would wire the horn in parallel, not series (if the power supply is e.g. 12V and each horn is 12V, but if the horns are 6V then wire in series)

i hope he meant he put the switch in series with the horns… otherwise that would be tres mal

parallel for electrical bits is good

Thanks. I should correct myself and say that I tested them in series, just for shits and grins. :smiley:

EDIT:

Could do that. I’m still waiting for somebody here to confirm on the wiring of the relay. Maybe it’s time to stop scratching my sack and get back to the autoparts store. Anybody know how to say “schematic” or “wiring diagram” in Chinese?

Actually, if the switch can handle the current (Ampere) to the horns you won’t need a relay.

I figure the relay is cheap insurance against burning out either the switch or something else deep in the wiring harness of the bike. I did some reading online about other dual-horn installations and they all employed a relay. Some of these installations were quite amusing. One guy put air horns in.

You will burn the little switch if you try to draw the whole current for the horns through it!

Motorcycle horn circuits usually are earthed through the switch. ie, the horn is fed with 12v from the battery and then the other wire goes to the switch. When the switch is pushed it connects to ground, completing the circuit. With me so far?

So, what you want to do is first replace the existing horn with the relay. ie, the relay will have 12v from the battery on one terminal and the other switch terminal will go to the switch as before. When the switch is pushed the relay will be energized and it’s switched terminals will be connected.
Then, you run your power wire for the horns from the battery (+) terminal. Use at least 12ga wire for two horns. Put a single fuse block in the run, as close to the battery as possible. Split the wire into two near the horns and connect it to one of each horn’s terminals, it doesn’t matter which one. The other terminal on each horn is then connected to a good ground. Also use 12ga wire for this.

Here is a good tutorial on relays.

Agree, if you are using the switch that is already installed it’s better / necessary to use a relay.

In that case my previous suggestion for wiring is not valid anymore, it needs to be reversed (change + with -).

[quote=“redwagon”]You will burn the little switch if you try to draw the whole current for the horns through it!

Motorcycle horn circuits usually are earthed through the switch. ie, the horn is fed with 12v from the battery and then the other wire goes to the switch. When the switch is pushed it connects to ground, completing the circuit. With me so far?

So, what you want to do is first replace the existing horn with the relay. ie, the relay will have 12v from the battery on one terminal and the other switch terminal will go to the switch as before. When the switch is pushed the relay will be energized and it’s switched terminals will be connected.
Then, you run your power wire for the horns from the battery (+) terminal. Use at least 12ga wire for two horns. Put a single fuse block in the run, as close to the battery as possible. Split the wire into two near the horns and connect it to one of each horn’s terminals, it doesn’t matter which one. The other terminal on each horn is then connected to a good ground. Also use 12ga wire for this.

Here is a good tutorial on relays.[/quote]

Thanks Redwagon! I’ll scope it out and come back later.

EDIT: Ok, checked it out and understand the principles involved now… basically I’m using the relay to isolate the the delicate little switch from the high-amp current path between the battery and the horns. It’s a SPST relay with four leads, so the switch energizes the coil which closes the contact on the high amp circuit: I get power from the battery straight to the horns. Now to figure out which lead is which.

I should have continuity between the leads which power the coil, correct? On the black and white leads I get a resistance of 101 ohms.

And… I should have an open connection between the lead from the battery to ground. Red will be the connection to the fuse next to the battery, and yellow will go to the horns. The horsn themselves will be grounded to a nearby lug on the forks. Gotta run, I’ll test this later.

Job done, horns installed.
Sound check here
: youtube.com/watch?v=_hFGgW4Pz4c

Good man! I have a pair of these on my bike and they sound wonderful. Notice how vehicles stop in their tracks when trying to pull out, looking for that all elusive bus while you sail by merrily on your way. They do have a pronounced effect! :laughing:

Cool!

I used to drive a car in Malaysia that had a louder-than-normal horn, cleared the path everytime.
Guess they must have thought a fourteen-wheeler was coming through … :smiley:

This is what should be a ilegal modification.

Horns should in genaral be ilegal and removed from the viecle upon arival to Taiwan and if produced here it should not be fittet in the first place.

I hate people that put the life off themself in the hands of horns and luck :raspberry:

Probably is… so what? Don’t the cops already have enough to do (or not do) rather than bother me about this?

Go ahead and hate me then. I for one ain’t going out into the mayhem with nothing but my dick in my hand. When some wanker taxi driver, or some scooter asshole with no mirrors starts drifting into my path, I require an adequate deterrent. If I were staying in Taiwan long enough, I’d look into fitting some of these:

groverairhorns.com/motorcycle/mcl.html

SA -
:bravo: :bravo: Well said! :bravo: :bravo:

Safe and Happy Motoring to you & yours!

Thanks TC,
I have room in the garage now, so I can put your new horns in next week.

I had truck horns on a bike once and every time I sounded them the lights dimmed. Guess I needed a relay, two batteries, and a better voltage regulator. Very effective though heh heh.