If there is someone nearer you, it will save you money, but, assuming you have a drum brake, I have a hub, check your retainer on the sprocket carrier and see if they buggered those threads up also, if they did not know to drill out the divot in the brake retainer, then they did not know it for that part either.

Good drum hub is $65, Disk is $75, ( but not sure if I have one of those at the moment, still sorting stuff from the move.

H.C.C.M.F. Local 6978
http://hondacb750parts.net