Per the badges and other indicators, it is a 74 R90/6. Depending on mechanical condition, it's probably worth somewhere between $2500 and $3500. It also depends on the location, since prices vary from place to place.
It appears to be in decent condition and the seat, tank, and fairing are worth quite a bit all by themselves.
What's the asking price?
Wanted: Dead, smashed, crashed or trashed gauges
BMW GAUGE REPAIRS - TACH*SPEEDO*CLOCK*VOLT METER *PODs & LIGHT BOARD*