With the way they pull air/fuel out of the crankcase, on a V-twin it's really hard to keep the 2 cylinders from fighting over the air/fuel.
I kinda figured that was what he was getting at. There are a ton of V-4 and V-6 2 stroke outboard motors out there. They must have something figured out to deal with that. I've never had the bottom end apart on one of those but as far as I can tell they have seals on the outer diameter of the crankshaft at each journal and partitions in the crankcase. V-twin should be able to work the same I would think.