Knife edged crank?

[spetz]

What does this mean?

Does it just mean there are no bumps or abnormalities in the crank?

And what does it mean to counter balance a crank? Or does this just denote that it's weight is the same as the pistons/conrods?

[Flanderz]

Knife edging the crankshaft is the process of grinding down the crankshaft counterweights into a “knife like” shape. This is done to reduce rotational mass of the engine and therefore increase hp by increasing efficiency. However, i believe this is only a race only engine. The countershaft weights are there to keep the crankshaft stable at higher rpms to ensure long bearing life.

[jimmeh]

Knife edging the crankshaft is the process of grinding down the crankshaft counterweights into a “knife like” shape. This is done to reduce rotational mass of the engine and therefore increase hp by increasing efficiency. However, i believe this is only a race only engine. The countershaft weights are there to keep the crankshaft stable at higher rpms to ensure long bearing life.

Knife edging the crank is to reduce the friction aswell. so as the crank spins it cuts thru the oil.