hummm i think i have seen better repairs.. but as far as retapping i would not do that.. that is a heli-coil in there its not tapped for the bolt size but rather the heli-coil's outside diameter

 

Worth a try, or as my granny said just before she fell off her Harley, "sonny, its just crazy enough to work."

I'd gook it up real good with the strongest epoxy you can find and give it a try. Smooth off the outside and get rid of the flux which could get in the lube system.

 

Smooth it of with an angle grinder and a flap disc? If I use a cut disc to remove the heavy do I risk exposing a fissure in the weld?

 

Chip away the flux w/ a chisel.
Contour the outside of the boss with a die grinder and carbide cutter.
If you find a fissure in the weld it will probably fail eventually anyway; hence the epoxy. All that extra braze glop on the outside doesn't add any strength to the repair anyway.