Helicoil Kits are pretty cheap(ish) on fleabay. Just checked and there are a few around £8.50 inc.postage. Sod's Law says that the other stud/bolt won't be far behind, so you'll have the kit all ready for the repeat sketch. You didn't say what diameter you want, but I guess for a scooter, it's not going to be too big. I might be teaching my Grandmother etc... but take care with the taps. They are reeeeel brittle. If one breaks in the hole, best throw the scooter into low earth orbit !!