> Displacement relates fairly directly to horsepower, > but not entirely, and horesepower doesn't > completely answer the question of 'how fast will > I go'. Not to get too far off topic but this statement is completely untrue. Consider a Honda VTX 1800 which has a displacement of 1795cc compared to a Honda CBR600RR which has a displacement of 599cc. Despite having 1/3 the displacement of the VTX the CBR600RR produces more horsepower (105.4 versus 94.6).