Motorcycle Electrical & Wiring

There are a couple of indicators of a bad ignition switch. The first indicator is if your bike will not start, and you know your battery and connections are good. This seems pretty obvious, but there are other things that can cause your ignition system to fail. If you have a neutral light, you can check to see if it is lighting when you turn your key on. If the neutral light does not come on, it may mean your motorcycle ignition switch is bad. Other indicators would include a loose-fitting key or the bike stalling when riding down the road.

This varies from manufacturer to manufacturer. Harley recommends changing your motorcycle spark plugs every 10,000 miles. This is not because the spark plugs have gone bad, it is simply because they are not as efficient as they were when they were new. Spark plugs wear over time. The edges of the electrodes will eventually burn down. Spending a few dollars to keep your motorcycle running like it should is a good idea. Check your manufacturer recommendations to determine when is best to change your spark plugs.

It depends on which switch you are trying to diagnose. The brake light switch actuated by your hand brake lever is a tiny momentary switch. If you listen carefully, you can hear it “click” when you apply your hand brake. If your brake light is not coming on, and you do not hear that “click”, it is a good indicator that your switch may be bad. Rear brake pedals typically use plunger mechanical switches. If your brake light is not working when you apply your rear brake pedal, locate the wires to the rear brake switch. Turn off the ignition. Unplug the two wires and jump the circuit with a small piece of wire. If you turn on the ignition and the rear brake light is on, your switch is bad.

There are a variety of variables that you need to consider when determining the average life-span of a motorcycle battery. AGM lead acid batteries will not last as long as some of the newer lithium batteries. Most lead acid AGM batteries have a 4 year service life span. If you live in a cold climate and do not maintain your battery during the winter months you will greatly reduce the life span of your battery. This applies to Conventional, AGM, and Lithium batteries. During those winter months it is a good practice to keep those batteries charged and in a warm storage area.

Most motorcycles use 16 to 18 gauge wire for the controls and lights. Items like starters and battery connections use ticker gauge wire typically 12 to 14 gauge.