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Made in Taiwan.
The second and third digits refer to the model - SI. The fourth digit in the serial indicates year of production (1997 or 1998). X in the serial indicates production Month (E to L - May to Dec). Y in the serial indicates production Month (A to D - Jan to April).
Bikes made in Taiwan usually had an 5-8 month production and shipping timeline before they were sold in bike shops around the world. Bikes welded in the later months of the year would normally be made for the following year.