The reason is because in the simplest form to describe an engine is "Airpump". How much air they pump "Via cubic inches" and any given cam will work at different RPM ranges for different cubic inches. Breaking it down to this form of 2 strokes make them and air pump "Intake, exhaust" and the 2 extra strokes that make them an engine "Compression, ignition" this is as simple as it gets.
Also every cam we sell that has a part number has been tested many times so we know how it runs.
