[Railcarmover]

Well I'm not a machinist,I know that.But you don't need to run a balancer or be a machinist to understand basic principles,as a mechanic they are valuable in understanding what you are doing.Its my opinion that in a street driven model a counterbalanced crankshafts are oversold.As others have pointed out there are inherent balance issues with a four cylinder engine that cant be cured.
I do know a flywheel stores kinetic energy,and although an engine might ramp up and down faster with a light wheel there are tradeoffs in engine longevity and smoothness of power transfer.Racing?the lighter the better,engine durability isn't considered.Street driving? Ford designed the A to get into high gear as fast as possible and leave it there,flywheel mass supports this effect.

Back to the topic,the benefits of a counterbalanced crankshaft are real,and can be supported by theory.However I contend the benefits don't necessarily outweigh the cost.