could anyone shed some light on both this and knifing the crank. and if you do knife the crank how does it effect balancing of the internals?

 

Knife Edging will help with windage... and the material is SUPPOSED to be taken off with balance in mind. You still have to high speed balance the entire rotating assembly. Polishing removes inperfections on the surface where cracks or stress fractures can start.
Schu

 

that was probably the most simple and direct answer ever. thank you for taking the time ....

 

Thanks to you
Peace
Schu