I own an FA50 that runs very well. The only "problem" I have is some weird rattling sound when I drive at high speeds. What makes the sound interresting is that it does not come from my motor/transmission. I am almost certain that it comes from the front of the moped; somewhere near the handlebars. I suspected loose bolts so I checked them all and they were all tightly screwed in.
I now have no clue where the sound can be comming from, but I have 2 more hints to help you guys analyse this. I hope they help:
1) The rattling occurs when I am driving at top speed (more vibration) and does not happen when I run at full throttle on my kickstand (tire in mid-air). This is how I deducted that it was from heavy vibrations.
2) The sound stops if I push on the handlebars firmly forward or if I pull them towards me. But don't think they move or anything... they are solidely attached to the frame.
I hope you can help me out.