Hello thumper talk! please dont hate me for being a noob on this stuff Im doing a rebuild on my 1990 cr250 front forks (Showa 45mm inverted) and I have the guide bushing and back up ring seated properly but the oil seal wont drive in that extra couple of MM to show the stop ring groove. It seats but just doesn't drive down that extra little bit to seat fully . I know the oil seal is on the correct way as well as the guide bushing. As far as the backup ring the manual doesn't really explain much on the inspection side. If anyone knows/has ran into this problem before your help will not go unnoticed! (apologies in advance if this is a previous thread) Ride on! -Allen b.