Complex sentence: Rotary disc valve induction ensure that the all the fuel charge is utilised and not partly lost as in a piston ported engine, as a result you get increased power, more low down torque and better response throughout the rev range.
Split into simpler sentences: Rotary disc valve induction ensures that the all the fuel charge is used and not partly lost (as in a piston ported engine). As a result it produces more power, more torque at low revs and better response throughout the rev range.