Blink
It has nothing to do with polishing, honing, or grinding. All of which are illegal. It has to do with the trueness of the crank. Rotax cranks from the factory are usually between .002 to .0045 out of true. The Rotax service manual I have to work to states that I need to set them at .001 max. All we are doing is cleaning them and trueing the crank to Rotax specifications. Period. No grinding, no polishing, no machining, no honing, no matching or sorting parts.
Sometimes a factory crank is better than .002. Those cranks will slip in the bearings. Cranks that are .004, will not. It’s nothing sinister, nothing illeagl, nothing outside of the intent. In fact, we are doing nothing more than setting them up exactly to the specifications set for by Rotax.
You can not polish, grind, machine, hone any crank or bearing in any Tag class. So why are we having this discusion?
When you rebuild your Vampire or Bilands, dont you have a specification on trueness of the crank? Do you not true them when you rebuild them?