So, that indicates a bad regulator/rectifier unit. You can do a plug-n-play from Mike's for XSCharge, perhaps a conversion from generic (I have not done, but a search may yield answer) or a MOSFET unit from Hugh's. I'd do the latter - opinion.
I'd also do the AC check before ordering, just in case there is an issue with the whole XS Charge.
https://www.mikesxs.net/yamaha-xs650-xscharge-pma-rectifier-voltage-regulator-replacement.html
https://www.hughshandbuilt.com/product/3-phase-mosfet-regulator/
I'd also do the AC check before ordering, just in case there is an issue with the whole XS Charge.
https://www.mikesxs.net/yamaha-xs650-xscharge-pma-rectifier-voltage-regulator-replacement.html
https://www.hughshandbuilt.com/product/3-phase-mosfet-regulator/