QuestionI just replaced the ignition coils on my '77 Honda CB550 with 3-Ohm aftermarket coils (and new plug wires). The bike ran great right after, but the next morning the main fuse was blown. When I replace the fuse, it seems to work just fine until I try to start the bike, then blows. The instructions that came with the new coils mentioned something about using a "1-2 Ohm ballast resitor" in the 12-volt line leading to the coils. I didn't do this (because I didn't read the instructions). Is that my problem, or have I just shorted some other wire when installing the coils?
AnswerI'd love to help but I ain't no electrician!
But let's put our thinking caps on. Wire is designed to carry a certain amount of current. If the current is too strong, the wire will overheat and start on fire. So fuses are placed between the wire and the power source so the fuse can blow instead of the wire. (Works the same in your house, too.) Fuses are essentially "warning lights." You only use them to tell you that something _else_ is wrong. A resistor, I'm guessing, is something that absorbs some of the current in order to keep the current at the proper level for the wire to handle it.
You recently added a new "power source." It likely puts out more power than the wires were meant to handle. So, the recommendation is to a resistor to mediate that. You didn't put in a resistor, so the wire's getting too much current, and the fuse blows.
My guess is that you are correct, your problem is that you did not install a resistor. But again, I know NOTHING about wiring, so you might want to get a second opinion....
Pat
