Hello Turbo, welcome to the forum.
The video shows bikes with a shift kit. Here is a link http://www.sickbikeparts.com/catalog...engau0soqt3924
The motors are referred to 80cc but we call them 66cc. The reason is the Chinese include the volume of the engine head combustion chamber to determine engine displacement. Which will make them 80cc.
Here in the west we do not, so they are 66cc.