This 250 cm³ single cylinder four stroke racing engine manufactured by NSU performed 21 kW (28 HP) at 7000 1/min. It became famous because of its drag link drive for the overhead camshaft. Two light, ball bearing mounted bars are by a quarter rotation staggeredly arranged, transferring the torque of the crankshaft onto the camshaft. The invention was done in the 20ies and was chosen by the NSU chief designer at that time because he absolutely wanted to avoid the at that time common chain drive. However, the design remained exclusive to NSU.