I know it's a 250R website, but I trust the opinions of our members...
I've been researching going over 500cc with my latest 450R dune/drag project and have found numerous builders who highly recommend micropolishing the internal engine and transmission components, for stress relief and friction purposes. I've called and emailed several places that offer the micropolish (and cryo treatment) services, but the most common practices are basically a vibratory tumbler with several stages of ceramic and aluminum media. At least two of the shops finish with a mild chemical bath to make the parts really shine at the time of delivery (essentially a quick bath in wheel cleaner).
After studying the media blends available through Eastwood and a few other companies, I'm thinking about trying it at home. Has anyone ever experimented with micropolishing, or had it done?