Ah! Teaching a Lesson Called Competition!

Skuld's been spending a lot of time with Belldandy, but Belldandy still wants to go to school with Keiichi. Skuld decides to take apart Keiichi's bike, but ends up upgrading it. Megumi notices the upgrades and starts to critique it. This upsets Skuld, who issues Megumi a mechanic's challenge.

Synopsis excerpt via Kitsu.