Cambodia not a bad idea, Thailand good option too
I've been over here 6 years, bought a bike(s) here instead of throwing away $2,000 plus the time and hassle of shipping/flying one of my stateside bikes here.
The Cambodia option is not a bad idea. Buying one in Thailand also a good option. Paperwork is always a bit tricky. I bought one bike here in Thailand just because the paperwork was legal. To get a bike legal can cost $1,200, or more!
Once you get a bike in here from the states you get a free pass to use it for 90 days in Thailand, then can overstay and pay a fine for up to nine months, then it gets really expensive.
Buying a legal bike in Chaing Mai, where I live, is another option. Everything is for sale over here, from H-D to BMW HP2, it's just how much you want to pay. I've not seen any Honda 650's, so suspect they were not imported. Heaps of Honda 250's though, and they make a good road bike for over here. I'vve a friend here in Chiang Mai who has a used F650, legal, that has almost no miles on it, for sale, and another guy had a 750 Africa Twin I looked at yesterday, for $8,400 USD, also legal, and clean.
Figure $2.50 per pound, flying, for your 650, and a day or 2 in bangkok to clear it and shake off the jet lag.... plus freight forwarder handling fees and Dangerous Goods forms... For that kind of money you could buy/use/sell a pretty solid bike from Mr. Lucky...
Dr. Gregory W. Frazier
Professional Motorcycle Adventurer/Indian Motorcycle Racer