Those of us with solid rims on V-Rods battle this all the time. Constant cleaning and putting on a protective coating regularly helps prevent pitting.
I've sanded my rims starting with a grit that can remove the pits (around 300) and working up to a 2000 grit sandpaper or more. This is a real PITA and is very hard work. Polish them with a mother's power ball.
Not sure if this is an option for you but you might also send them out and have them chromed.
During my first motorcycling lifetime, 35 years ago, there was a process used by riders who got tired of forever polishing cast aluminum parts, because within a few days or weeks, small spots of oxidation would start to form and if you didn't stay right on top of it, the pitting would start again.
At a microscopic level, cast aluminum is porous, like a very fine grained sponge. Those porous areas give oxygen a chance to get in under the normally very tight thin protective oxide layer that makes aluminum generally very durable, and it in in those microscopic cavities where the corrosion process starts again.
The solution used by some people was carefully choosing the right blasting medium, not sand, more like small steel balls, today maybe even hard plastic balls and bead-blasting the cast aluminum surface, to hammer it closed so it was no longer porous. It would be like having a thin layer of densely forged aluminum over the porous cast aluminum sub-surface. This would tend to change the surface texture, if you had V-Rod wheels with some texture to them, but if someone is talking about sanding rims anyway, they are going for a chrome bumper smooth finish anyway.
The good part about if you really get a highly polished aluminum surface to holdup, is that polished aluminum is really prettier and brighter than chrome.