I know this is an old thread, but I just had what seems to be the same problem on my Speed D7. I'm posting a photo. The derlin (plastic?) cover over the metal 'slider' in the handlebar latching mechanism broke. The screws in the plate were not overly tightened, and the plate slid freely. No excessive force was used to close the latch. My bike was only a few weeks old. This seems like a design that is just asking for problems. Does anyone have a suggestion for a good solution short of waiting for Dahon to replace the derlin part with the same questionable part? I was expecting a much more robust design given the price I paid for this bike.