Speed up your Lego XL motor
This is a how to make you XL motor faster but it will be weaker
You will need a drill and a I used a 2.5 mm drill bit. It doesn't matter to much just so long as the motor's shaft fit through it, and the shaft is in the middle.
The setup that I use keeps the shaft from coming away from the gears.
If you have anymore questions then use the comments section down below, and I will try my best to answer them.