Originally Posted by T-Mar

The BT prefix of the serial number indicates that it was imported to Denmark by Taarnby, while the U suffix indicates 1981. However, if it was late 1981, it could be a 1982 model. The presence of SunTour Cyclone Mk II, would suggest the latter, as that was the debut model year for this version. The Shimano crankset appears to be a later replacement. We've had European mid-range Nishiki turn up under names like Trim Master, Road Master and Race Master, so it's likely some variant of the Master model name.