View Full Version : Ironhead neck cup conversion and 39mm swap

02-21-2014, 9:57 AM
hey guys, I'm sure this has been covered in here, but I cant seem to find it. ive got a set of 39mm forks off a '06 sportster and I was wondering which neck cup setup I need to get, that has the fork stops in it. a buddy put a similar setup on a big twin and his lower neck cup has the external stops right on it. will that bottom cup press (or just fit) into an old ironhead ('77)?