caps lock off!
just to clarify the front end. does the stem clamp on to the forks rather than the old shafted system and have the forks got any thread on them
if it is a full clap on system with no threads on the fork then it will almost certainly be 1" 1/8' up front.
the bit thats baffling me is that the 1" 1/8' cups are too small for the frame
does the bottom ring from the 1" 1/8' headset fit on the forks