What brand of rear hub and is it a coaster? What sized wheels? It looks like a Raleigh 20 clone. The earlier Dahon's had a goofy upright bar that went up to the head tube.
i have a dahon w/ the ugly upright bar ya mentioned, its hideous, but thats part of why i dig it so much! i cant wait to get started rebuilding it. im stil thinking its gonna be mounted like a continental kit, but i have to get a strurdy frame first...