Explanation of Motorcycle Solenoidsby Lewis J. Fagleman
In the late 1960s, motorcycle manufacturers began installing electric starters on motorcycles, replacing their tiresome kickstart systems. A solenoid is one of the key component in electric starters, used to supply the motor with electricity.
The wire supplying amounts of electricity to the starter motor is thick, therefore a special switch is needed to allow the power to be turned on and off. A solenoid does just that using a small wire connected to an ignition switch on the handlebar. This small switch operates an electromagnet which acts as a larger switch for the thicker, more powerful wire.
If a motorcycle will not start, the two components which should be tested first are the battery and the solenoid. Should the battery be in working order the solenoid may be corroded inside or the starter wires may be corroded.
Rust and faulty connections are the main culprit for solenoid issues, so taking them apart and removing any corrosion substance or dirt can often prevent many problems. Replacement of components may be required should there be significant damage.