Hi All, 2 are listed by suppliers with 20.64mm and 22.22mm bores. There are other different dimensions described such as overall length and pushrod length, as 2 different servos were used in the 1982-1992 model lifetime. Does anybody know the original part number for the earliest type m/c or its actual size? or does it matter as many people just bolt on the bigger m/c as an upgrade? Thanks!!