"Brass insert."
I had that problem with my stock yamaha tank, here's what I did
I carefully cut into the plastic immediately around the insert with an exacto knife to free the insert.
right at the edge of the brass, then I cleaned up the hole with a round file. used JBweld two part to glue it back in. i applied the JBweld to the insert first, then some to the walls of the hole in the tank
If the insert is cross threaded, clamp it in a vise, and try to re-tap it, if it's really fried, drill it out and tap it the next size up.
Do this before you glue it back in. Also you might want to file a mm or two off of the back of the insert before glueing it in so it sets flush, also liberally apply some grease to a bolt, not the one you plan to use, and thread it into the insert before you glue in to keep the glue from filling in the bottom of the bolt hole. let it cure, take out the bolt. install shrouds, good luck