It's not a glamorous component, but you're stuck without it. Your motorcycle's regulator-rectifier turns alternating current (AC) produced by the charging system into direct current (DC) and also controls the charge going into the battery. That's vital because enough power at idle to run the engine and any accessories, which is about 20 volt AC, jumping to 100 volt AC when revved.
Any excess current is converted into heat, which is why a regulator-rectifier needs to be mounted in an exposed position to use airflow to keep it cool – and why it's kitted out with fins, as you can see in the picture. But that means it's also exposed to dirt and moisture and the block connectors can get grimy and increase resistance and heat.
If your motorcycle is a few years old it's worth checking the condition of those connectors as 80 percent of the time it's increased resistance there that starts to stress the regulator-rectifier itself. Cleaning them, then sealing them with non-water-based grease is good preventative maintenance. Some manufacturer had once a massive recall on motorcycles because the 'blue gel' used to coat and protect the regulator-rectifier's circuit-board by conducting heat away, wasn't hot enough when injected into the regulator-rectifier case during manufacturing. This left air bubbles, which allowed the internal heat to build up enough to cause failure within a few thousand kilometers.
Generally, a failing regulator-rectifier means your battery doesn't get charged and will run flat in less than 100 kilometers – leaving you stranded with a dead battery. Overcharging is rare, and the result is that bulbs will blow or the battery will get 'cooked'… and a new battery is also needed.Tag: MaintenanceRegulatorRectifierElectricChargingBatteryACDCvoltageAC/DCHeat