This is
the page of Y's Ueno. I am not sure about riding at Y's. Also, I do not know how your Japanese is, but at Y's Ueno it may be hard to find someone speaking English. At Loro Slow they will let you ride and nearly everybody speaks decent English. However, I do not think they have Dahon or Tern. Loro may give you a package deal when you buy accessories together with the bike.