The Universal Mikuni Fuel Pump is the standard in fuel pump upgrades.  Can be used on everything from a 50cc scooter to a Evinrude boat motor.  There's never been a better product for reliably and efficently moving gas from the gas tank to the engine

For scooters specifically, this fuel pump is best used for bikes that have tanks below or at the same height as the engine like the Icebear Maddog or Honda Ruckus.