the Cdi is located under the battery box on the 87 the battery box has one 10mm bolt holding it on then there is a metal brace under the box you have to take off two more 10mm bolts then you go in from both sides of the bike above the carbs there is two bolts on each side of the bike that takes a bracket off that holds the four coils and the CDI you have to unscrue the four coil wires and unclip four electrical connecters and two connecters off the CDI then take the unit out of the bike turn it over and take two screws out and that is it that takes it off the bike I really want to thank you and this web sight I haven't had good people like this help me out like this in a long time my number is 480-699-4986 If I can return the favor just yell.................