THIS IS THE ORING THAT IS VERY IMPORTANT,, THAT IT DOES NOT LEAK AIR BETWEEN THE CARB AND INTAKE MANIFOLD !! WILL WORK ON CT70'S KO TO 77, CT90'S ALL TO 1977, ALL ATC90'S AND THE 73 & 74 ATC70'S. *O-RING FRONT OF CARB FLANGE CT90K0_THRU_1977 ALL_ATC90'S CT70_KO_TO_77 (84L) 84L$3.85