The road between Yunnan and Lhasa is closed to foreign riders (in guided tours) until August for construction. They've got some sort of national road inspection happening this year and half the highways in the country are being resurfaced, it seems. What a pain. I'm on tour in China right now and will be passing from Yunnan to Nepal starting in mid June. I look and speak Chinese though, so that doesn't help you. If I end up in a PSB holding cell, atleast it'll be a good story.