Was rooting around in some old technical stuff. Found this. Some basics tips for troubleshooting Voltage Drops. Mess around with XS650s for long and you will know all about these.

Voltage Drop Troubleshooting Tips

page 01

page 02

page 03
You will need at least one of these…

multimeter – volts ac/dc – ohms
Freaky shit? Need a tutorial? How to use a multimeter.