Motorcycle Repair: 83 550 nighthawk, filament bulbs, double filament

Question
My dad gave me a 550 nighthawk after my sister laid it down and broke off all the turn signals. I have replaced all the signals and need to replace the switch. I finally found an aftermarket switch, but I need a wire diagram to hook it up. My bike has been down all summer & I need to ride before I loose my mind. Thank You, Amanda

Answer
Amanda, I don't have a wiring diagram for a 550 Nighthawk. Putting an aftermarket switch may be more hassle than benefit. The switch has to have a horn switch on it, as well, and there are a couple of different ways that Honda used the switches to operate the horns. Some just ground the hot horn lead wire to the handlebars. If the bars are insulated then they run the wires through the switch and back out to another source of ground.

The most common wiring circuits for Hondas is that they run a switched battery lead through the flasher, then it goes up to the handlebar switch, usually as a grey wire.
From there, the power goes into the center of the switch contact plate, where it can be selected by the switch lever to either blue (right side) or orange (left side) wiring that leads out to the signals, themselves. The signals have to be grounded, too, in order to complete the circuit. Some are grounded directly through the mounts and others ground back into the wiring harness.. usually the GREEN wires, out under the seat, towards the back of the rear fender for the rears.

Go here:
http://www.powersportspro.com/partsfish/login.asp

Sign up, log in and select your HONDA motorcycle model option... CB550SC, then you can look at the main parts illiustrations, but no wiring diagrams!

Front signals have double filament bulbs for both turnsignals and running lights. Rears are a single filament bulb and it appears that they are grounded through the harness connectors, because the signals are basically plastic bodied.

Looking at the signal switch illustrations, there are a LOT of wires and specialized connectors coming out of them. Try to see if Ebay or some motorcycle salvage yards may have a usable switch assy, rather than trying to rewire the whole bike! Find a shop manual for the 550, 650-700SC series machines and it should have a detailed wiring diagram in it, if you decide that you just have to use that a/m switch!

Bill Silver