i dont think a 650 is not capable of touring at all. that being said, the bigger touring bikes offer alot more in terms or room for rider and passenger, better suspension, better brakes, more and bigger luggage options, and a better chassis built for the job. most 650 bikes are built cheaper to keep cost down so they are more affordable to the public. which is in fact a great thing, but also a draw back. My good friend has a new NC700X, cool bike, but for 2 up touring just in no way would suit my needs. its underpowered for my liking, the suspension is under sprung. Its also the old school style forks (which most 650 and cost effective bikes are) which has very little damping, tons of brake dive! no adjustments on the forks, only preload on the shock. loaded up with luggage and a passenger would concern me greatly not only because of the lack of power, but because the suspension, if its undersprung for a solo rider its gonna be 10x worse loaded 2up. also a passenger would be cramped on that bike. which inturn would make the rider uncomfortable. i guess it boils down to if your going to be doing solo touring or 2up. i much prefer a bigger motor and a bike built to hold more weight and do the job with that weight.