So, why are you trying to use a non-stock carb?
Don't want to spend the money? Did you just have that on hand?
There are stock carbs for the Honda Express nc50 moped on ebay all the time. Heck you can probably get one massively cheap on this forum.
Good luck in any case. Thanks for posting video.
FYI: here is a list of Bing carb #s if anyone is interested: http://www.mopedarmy.com/resources/articles/bingcarbs/