Hi, Steven before testing any electrical component in the Starter System it is "IMPERATIVE" that you have a fully charged battery of 12.5 volts or more and be able to pass a proper "LOAD" test if necessary, you may have a preliminary reading of 12.5 volts or more but little or zero amperage, the battery is faulty and must be replaced. AGM type batteries fall into this scenario more so than lead acid batteries.
A motorcycle starter relay is an electronic mechanical switch that has a small coil winding around a piece of metal that requires low amperage and thin wires to be activated. When you turn on your ignition switch power 12 volts is sent to the relay coil which in turn becomes a magnetic contact point that pulls a spring-loaded contact point to itself completing an electrical circuit that allows more amperage necessary to be accessed by the starter solenoid which in turn acts in the same way as the relay but on a larger scale with its stronger heavier contacts making available the necessary amperage to turn the starter motor. If your battery has low voltage it, in turn, makes the magnetic contact point weak in trying to pull its counterpart to make a connection. These relays are usually encased in a plastic housing that may or may not be sealed depending on the quality of the product. When activated they will produce a small amount of heat to their metal components which in turn can create the perfect environment for condensation to form depending on weather conditions and how careless you may be with a water hose or sprayer while washing your bike. After a period of time, several months to several years depending on the circumstances this condensation is the starter button for electrolysis and the slow build up of corrosion which ends by preventing the magnetic contacts in making a solid connection and alerts you to this situation with the customary greeting "CLICK or BUZZ". The relay is inexpensive and needs to be replaced however in a pinch they can be forcibly opened cleaned and resealed with silicone. In a nutshell, motorcycle starter relays take in low amperage and send out higher amperage when activated and for curious minds, the voltage remains constant at whatever your battery reads at the time.
For more information about your issue and valuable "FREE" downloads that you will need please click on the blue links below. Good luck and have a wonderful day.
Main relay buzzing CEL Flickering WTF Honda Tech Honda Forum Discussion
Honda CBR125R Owner Manual
Honda CBR125RW Owner Manual
Btw, I’m available to help over the phone in case u need at https://www.6ya.com/expert/gregg_c0ec1df182c7330e