Maybe you need to convert to a Quill stem? Koga of NL had a widget to do that with threadless forks .

Merry sales has one for 1" threadless forks , the ID of a 9/8" thjreadless fork is 1.0"

here Page 113 "Quill-inator" * so you need to step down the diameter ,

perhaps Via Brazing a 1" tube inside the 1.125" one.

* http://www.merrysales.com/merry_cata...ricingfree.pdf

this is a distributor catalog you have to find a retail shop with their wholesale account.