If you're going to start doing electrical work and lighting mods on the bike, it's great to have a basic knowledge about relays. They can really open up some good possibilities for you.At a minimum, it's good for you to have a knowledge of how they work, and what all those abbreviations mean, because you'll run into these quite a bit if you're out there on the bulletin boards.
You'll need to be able to use relays to wire up fog lights, air horns, and you couldn't do a wigwag mod at all without the use of relays. So check below and at least get a basic knowledge of what these gadgets are and how they can help you!
Relays are nothing but fancy switches. The connection is switched by turning an electromagnet on and off.
The diagram below shows the inside "guts" of a common relay, the "single pole, double throw" relay. "Single pole" just means there is ONE contact arm (the bent thing shown in yellow) that can swing up or down to make electrical connections. "Double throw" means that there are TWO possible connections that the arm can make, which are labeled as connection "87a", the connection that the arm makes at rest, and connection "87", the place the arm connects when the coil is activated.
The "coil" is just the wire going from pin 85 to pin 86, wound around an iron core. When current passes through the wire, a magnetic field is produced which will attract the metal contact arm (the yellow "throw"), pulling the contact off 87a and onto 87. So that's how applying current at 85/86 effectively throws the switch.
Try to remember "87a" as "87-always", meaning that the natural state of the relay is to have 87a connected to current at all times, unless you switch it by applying current to the coil.
Note that 85 and 86 are interchangeable. You can hook 86 to ground and 85 to power, or the other way around. All that matters is that when current flows through the coil, the current flowing through pin 30, which previously flowed out 87a, is now redirected to 87. This means that a light attached to 87a now goes OFF, at the same instant that the light attached to pin 87 goes ON.
By default, the throw arm will always be connected to 87a, since it is held there by a spring. It will remain there until the force of the activated electromagnet pulls it off. What you've just learned is the function of an SPDT relay. You can probably now guess why this is the center point of a "wigwag" setup, because this is exactly what a "wigwag" is: you want on headlight to go ON, at the same time that the opposite headlight goes OFF, then switch back again.
Here's what the SPDT relay looks like in real life. It is a small black box with these "pins" or "contacts" sticking out of it. Even if they are not marked, the pins are recognizable because they are ALWAYS arranged in this standard pattern. You'll recognize 85/86 first because they're along the outside and parallel to eachother. 30 is always pointing the same way as those two coil pins. Then you know that 87a will be found in the middle.
Many other relays are available. The single pole-single throw relay has only one "pole". That means it has only one swinging contact arm, just like before. The "single throw" means that the contact arm can make only ONE possible connection. So as you see in the diagram, there is no 87a. The contact arm, at rest, contacts NOTHING. When the coil is activated, the arm swings over and connects to 87.
So the bottom line here is that a light bulb attached to 87 goes ON only when the coil is activated (that means only when 86 is HOT and 85 is ground). The light bulb at 87 is OFF at all other times.
This is a very common relay used in automobile and motorcycle lighting applications. For example, you can attach the bike's running light hot wire to 86, ground 85, then connect the battery + to 30, and connect your new super cool foglights to pin 87. This way the foglights can only be ON if the bike is turned on. That's because your control wire, 86, will only be activated when the bike is on (because it's attached to the Suzuki brown wire, the running light wire). So this way , your foglights at 87 are "linked" to the bike's ignition. The lights can only come ON when the bike is on. And the lights go OFF as soon as you shut the bike off.
This is a HUGE advantage over just hooking lights to the battery + alone, which allows you to walk away from the bike with all those lights still ON --- bad idea. Also, the use of a relay gives you another advantage over just using a switch to turn on your foglights. If you just wired fog lights through that brown wire, then you have just placed an additional HUGE current load on the brown wire that it was not intended to carry. This will cause a blown fuse (if you're lucky), or a melted wire and fire(if you're not lucky). When wiring something like foglights, which have a large current draw, you can allow a very small current in one wire ( the brown wire ) to "switch on" the current in another circuit (the headlight or foglight circuit), without adding any extra current draw through that brown wire. So you add new heavy gauge wires for your fog lights, to carry their huge current draw, but those wires only get current if the relay sends it their way.
Though many other relays are available, if you have a simple understanding of the SPST and SPDT relays, you're well equipped to handle most tasks on the Gixxer or an automobile