1969 cb450 max horsepower: 45
2010 harley sportster 883cc hp: 46
That's to say: the cb450 generates about the same horsepower with half the engine (displacement is 444cc). I had heard that the engine was high tech for it's time, and that they stopped making it mainly because production was too expensive; I had never really appreciated just how advanced it must have been.
How does it make so much more power? I suspect it has to do with the peak rpm being nearly twice that of the harley's: 9000 vs 4600.