Vietnam: no, not even under 175cc, those who claim theyve done it, have probably been just very lucky. China, I dont know, surely wont be easy!! Im actually trying to find that out myself, as Im planning to ride from Europe to Thailand next fall. There have been some encouraging reports, though, from people who say they´ve managed to cross, but from Kazakhstan, that is. Laos is several thousand kilometres away of course, but one would figure the rules at the border would be the same.. or then theyre not! We tried to go to Vietnam a few months ago, but it turned out to be just a good lesson about the way they reject bikers.
I would also be very thankful for any info on this.
I entered "China" to the search, got 4 topics plus the 1 ive started myself. Most deal with travel inside China, or are questions (is it possible) similar to mine. Cant say theres loads of information about this topic, not on that keyword at least.
Maybe some other forum on this site has more, then.