I contacted the company that is importing the Yamaha gear in our country. I've got a copy of the advertising for this bass. It's made till 1994, and official retaling price was F 2345,- (wich is round $ 1000,-).
The neck is bolt on, the scale 33-7/8 (860mm). the neck is maple, finsh rosewood, ash body.
They came in three colours, transculent Black (mine), transculent violet and natural satin.
Well that's all for now. Still hope to find out more and still like the bass, if another one occurs at a reasanable price I would buy it and if this one was stolen, damn it I would want another right away.