I can't see the pics but it sounds like a circa 1985-1987 Bianchi Limited. We can eliminate pre-1985 because it was spec'd with SunTour Cyclone up to 1984. Non-aero levers and six speed indicate Shimano New 600 EX and would date it 1985-1987. If it has the Colorado Springs decal and SIS, it's almost certainly a 1987, though a very late 1986 model is also a possibility. I'm not sure that Bianchi spec'd the SIS version upon it's release in 1986, so non-SIS could mean 1986, in addition to 1985.
FYI, Japanese manufactured Limited models go back as far as 1981. In the late 1980s, manufacturing of some of the Japanese models, like the Brava and Limited, got moved back to Italy, after the re-valuation of the Yen relative to the Lira made Italian manufacture of these models economically feasible.
If the OP would care to submit the serial number, we can verify the country of orign and may be able to establish the exact model year.
Last edited by T-Mar; 11-10-10 at 08:02 AM.
Reason: typos (and I probably didn't catch them all)