Engine Gears and Base Clutches are the defining gimmicks of the G and GT series of the original Beyblade toy line, and my personal favourites.
Basically, the Engine Gear is a Spin Gear (the core of the Beyblade, on which every parts connect and on which the launcher tabs hold) powered by a wind-up motor—a set of gears and a coil spring—that when activated, makes the tip at the end of the shaft spin vigorously. Of course, it is not without flaws: for one, the tip spins independently from the rest of the Beyblade, meaning only that part gets the boost; for two, it greatly reduces the customization options as they were present in the V2 series; and for three, its power is underwhelming. Despite this, there’s something about the idea of a spinning having a super-powered heart and being a “marvel” of engineering: who knows, maybe I’m just hopelessly romantic.
The Clutches determine when during battle the motor activate.
Below are three short videos (i.e. one video in three languages) explaining the basic principle of how it works.
If anyone speaks Italian and is of a mind to tell me how my translation looks, I’d welcome the criticism.