On my Honda 50cc GHX, the govenor was set @ 7800, has been removed so top rpm is in the 8200 range on the level with my 210 lbs, and 6'3" frame catching air.
From what I read, most agree that the Chinese 2-strokes turn in the 6K range, with a few people getting away with more.
I haven't busted a rod yet, but I've seen 8600 while laying down to reduce drag and on a road that is about 1.5% downgrade.