Laos / China only at Boten (L) / Mohan (C). However China now refuse entry to bikers without the appropriate travel documents and permits, which have to be issued by the authorities inside China. The exact documentation required is somewhat unclear, but it appears as if you must at least have Chinese vehicle registration, insurance and driving (riding) licence; (plus guide / escort?) and these are not available at the border. This all a bit too tricky – how do you get these on the border, “outside” China. So you can scrub China off your riding list for the time being.