The carbed SS bikes were technically from 91/92 - 97 worldwide and 91/92 - 98 in the US (the 900FE and 900CR for the US market were model year 1998).
98 was also the year of the newer FI SS bikes. Because of the latter, most refer to the SS bikes as being from 92-97. But there are some carbed 98 bikes worldwide.
As for differences in model years, see...
http://www.geocities.com/edwyun/myears.html
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