wiring
if i purchase the wiring diagram on ebay for the 1980 xs will this be all i need?

I'm not exactly clear what you are after, but I have found these schematics to be useful to determine the names of the electrical system components... http://www.bikebandit.com/houseofmotorcycles/yamaha-motorcycle-xs650c-1976/o/m8270 Or check out these wiring diagrams if you are building a custom... http://www.cyclepsycho.com/yamachopper/wires/wires.html I see they have a diagram for a stock '81, so maybe it is similar to your '80. I don't know if I would trust these diagrams entirely since I have never used them. Maybe you can save time and $ by not having to purchase them. Hope this helps,