Yes, your soda machine is a bit big, but the mechanism is nice.
Speaking of soda machines, I just create the first group MOCpages dedicated to these creations. However, apart from me, nobody yet joined this group. I have already sent an invitation to many of the creators of soda machines, among them to you. Visit this group http://www.mocpages.com/group.php/21501 and if you're interested, join it and publish it your soda machines. I give power of MODERATOR to the first 5 people who join the group.