Shame on me... I've had the 1991 "Eldridge Grade" in mind (triggered by "neon yellow", I'd say):
Nevertheless, the 1991 Marin catalogue states for the Palisades:
Front Fork: Marin Full Cromo 1 1/8"
Headset: Ritchey Logic 1 1/8" Sealed Black
Maybe in 1990 diametres were different.
Anyway...
Many thanks, I could pick up the parcel from yours at the post office today.
it's all in good order and I look forward to completing the brake arms again.
Cheers and good luck with the sale of the rest.
Sorry for deviating, but are you sure you employed a 27.0 Thomson seatpost? I think I had to resort to a 27.2 seatpost in order not to stress the clamp too much. Maybe you check the gap at the clamp.
Cheers,
Thomas