I have a servi with 58-up glide type frame and 57-back 45 flathead springer. I have been running stock 45 springer neck bearting cups with shims, but cannot keep slack out of front end. I just bought the V Twin conversion kit to install 45 springer on BT frame. The bottom cut will press in, however the opening for the top cup starts out at 1.3075" wide and about 3/4 inch down goes down to 1.225". My parts book shows the same parts number for BT cups as 58=up servi frame cups. Why is there a change in width in the top of the neck frame. The repo cups measure 1.3205" at the recess that fits into frame neck. I think I will have to turn the better fitting bottom cup down some to get it to fit. Does anyone know why the upper hole in frame neck goes from 1.3075" to 1.225" , I don't believe any stop cup will fit this. The holes in the neck look stock with no mods. Help needed. Will be out of town for about a week. Help.