are there benifits to knife edgeing the crank or does it weaken the crank? has any one knifed the crank.... let me know

 

lightened rotating assy. also when the do it, they also balance the crank..

 

knife edging has it's benefits, allowing you to rev quicker (by cutting threw instead of hitting the surface of the oil). As for the fatigue of the metal it pretty much depends on how much you take off (taking to much will lose it's stablility of the strength on tremendous high rpm) and how well the rotating assembly is balance.