no the # is the size of the motor in Cubic Centimeters or CC`s ... a saito 91 is not more powerfull than a saito 100..... but a YS 110 is almost as powerfull as a saito 150. not because of displacement ... because the YS motors are supercharged... they are 2 different animals..


I am talking YS 110 or Saito 150.. both of these motors you wont be dissapointed with the YAK