Meaganhein

I am building a 1977 xs750 as a project bike and I’m having electrical issues. Every time I try to get it to turn over the main fuse blows. I have inspected all the wiring from the headlight bucket to the wiring harness and i can’t find any shorts. I also used a multi meter in place of a battery and still had no luck. Does anyone have any idea what this issue might be or even how i can continue to troubleshoot? I’m at a loss.