Is your machine still under warranty? Assuming you've already verified your battery and cable connections are good, you will need to first verify the AC voltage coming from the stator because that is where the charging system voltage originates, and then test the DC voltage coming from the voltage regulator. If you're handy with a multimeter, I will list instructions tomorrow once I get back to my office where my tech manuals are. 9 times out of 10, the issue is either the voltage regulator, a loose wire, or a weak battery. But occasionally, something happens to the stator or flywheel magnets, so that is why we first test the source voltage from the stator before testing the regulator.