THESE WILL NOT FIT THE CT90'S SORRY. FOR THESE EXHAUST SYSTEMS TO WORK ON THE CT110'S YOU MAY NEED 2 EA OF OUR 28i FLANGES, UNLESS YOU HAVE SOME FROM A 50 OR 70 LYING AROUND SCROLL DOWN TO SEE MORE.... @ *MUFFLER_TO_HEAD 1/2_MOON_FLANGE Z50A_68_TO_78 (sold_each) 18233-040-010 1/22M (28I)THESE FIT ALL Z50A'S. 28i @ CLOSER LOOK