Wanted - 78 XS400 Cam Shaft

[78YamahaXS400]

Looking for the cam shaft for a bike I started helping my Dad and Brother rebuild. The tip was broken when a screw was overtightened. We're trying some JB Weld, but I don't have a lot of confidence in it. I haven't been involved as much till more recently, so I'm kind of finishing what was started.

Thanks,
Chris