Now
In light of their usefulness, it's strange that most manufacturers don't include them as standard equipment. A few bikes have had them. However, their manufacturer's indecisiveness is plain because on most of these machines, the keyswitch must be turned on to use the hazards. Doesn't do you much good when making roadside repairs or going for a can of gas, does it?

Wow!
Adding hazard flashers is cheap, easy, and effective. Do it yourself and you won't have to plunk down forty bucks or so for a bulky black box with an absolutely atrocious General Motors dashboard pull-switch sticking out of it. I have used the following system on my own and others' machines, and you can too.

How
There are actually two ways to wire this up. One is cleaner and more like OEM, but requires that you give up your bike's engine kill switch. The kill switch will be used for the on/off for the flashers, and will no longer turn off the engine. If you use this method, you are on your own, and I am not going to be responsible for your not having a kill switch. Blah, blah, blah...(legal disclaimer). The other method is not as neat, but you get to keep your kill switch. Chose your method, and proceed.

Method #1

Method #2

Before beginning, here are some general electrical work tips. First, disconnect the battery while digging into your electrical system. Second, solder -- don't crimp -- all connections, using 60/40 rosin-core solder and 18 gauge wire. Third, for factory-like pull-apart connections, use Honda's or Yamaha's OEM terminal kit. Order the kit, or just the individual terminals (makes more sense). It's the same kit (and parts) from either manufacturer, but it will make stock-like connections that you will be proud of. Remember however to still solder the connectors to the wire instead of crimping them.

For either method, you will need the following basic items. At any auto parts store, pick up a universal DOT #552 flasher unit. The DOT #552 flasher is load-independent, which simply means that unlike most OEM flashers it doesn't matter how many or what kind of turnsignals are attached to it, it flashes at the same rate in any case. This is the ideal thing for hazard flashers. Also pick up a few feet of stranded copper, 18 ga. "primary" automotive wire. This is general purpose connecting wire that approximately matches what is on your bike. Purchase a 1/4" eyelet, either from the terminal kit or from an auto parts store. Finally, pick up some shrink tubing, an in-line fuse holder (Radio Shack #270-1281), and a 10-amp fuse. Open the fuse holder and solder the crimped-on connectors before proceeding.

Method #1
For this method, pick up a package of diodes, Radio Shack part #276-1141. Find and disconnect your bike's right handlebar switch connector from the wiring harness. With diagonal cutters, slit the plastic sheath­ing of the switch's cable to within three inches of the switch assembly. Don't use a razor blade -you'll ruin the wir­ing.

The following directions are for Hondas. You will need to figure out how to translate the connections and colors if working with another brand. Follow this closely. We're concerned with three wires inside the sheathing. First, find the splice made by the factory of two black wires, Kill Switch Figure 1. Separate this splice to isolate the kill switch's power feed from the rest of the system, Kill Switch Figure 2. Tape-insulate the ex­posed bit of the still intact black wire. To the freed wire, add about five feet of wire, the #552 flasher, the in-line fuse holder and fuse, and the 1/4" eyelet. Solder and shrink­ tube. This completes the power-in side to the newly appointed hazards switch. Now, moving toward the connector end of the cable, cut the black/white wire (black with a white stripe), Kill Switch Figure 3. This removes the ignition coil(s) from the kill switch. Splice on a couple feet of wire and solder in the two diodes. The diodes will isolate the left and right turnsignal circuits from each other. There are two things to think about regarding diodes. First, pay attention to the diode's markings in the illustration. This circuit won't work if they're put in backward. Second, when soldering the diodes, grip each one with pliers between the soldering gun and the semicon­ductor itself to prevent heat damage. Still with me? Just one more step. Splice the loose black/white wire onto the still-intact black wire, Kill Switch Figure 4. This connects the ignition coil(s) to power again within the system (after the keyswitch). Now just tape the sheath­ing back up, and use a small zip tie to finish off your taping job. Attach one of the diodes to the light blue (not the light blue/white) wire, and the other to the orange (not the orange/white) turnsignal wire in­side your bike's headlight shell or fairing. See
Kill Switch Figure 5.