The large number plates were far more about aero than they were about rider identification. The rear number plates were used to fill in the gaps back there that created buffeting (and therefor drag). The front one was clearly a "cheater fairing". When you look at the rear tailpiece of bikes in the later 1980s and early 1990s those areas were filled in with actual fairings ... in the earlier years since production bikes had no "full fairings" or large tail sections the number plates were used for that task.Looking at all these really awesome old photos makes me think about how technology has advanced and helped the sport.
This is the greatest advancement in motorcycle racing tech I’ve seen come along in my lifetime.
God those old HUGE number plates were FUGLY!