This is Kit 00103 from Boyer Bransden, the Micro Power Ignition System for Yamaha XS650 / TX650 1970-1984. The Micro Power ignition provides almost total control over ignition functions. This kit is designed to work with a 12v dual output 4.5ohm primary resistance coil, this replaces your auto-advance and points plate and gives you the advantage of electronically advancing your timing to get optimum performance out of your XS650. Set it and forget it, no more messing with points!
You can view a pdf of the installation instructions for the Boyer Bransden Digital Ignition System for Yamaha XS650s in the pdf below.