I made 4 sodas on Friday, 3 ginger ales (Yooper's, mease19's ad my own recipe) and a lemon soda (this one from chickenetti http://www.homebrewtalk.com/f171/light-lemon-soda-259591/
). The three ginger ales carbed fine, but the lemon soda did not carbonate AT ALL.
I did waiver from the recipe by using bottled lemon juice rather than fresh (it's what I had). Did that alone keep the yeast from being able to survive long enough to eat the sugar?
I used a pack of Lavlin D47 rehydrated in 8 tablespoons of warm water, and then put 2 tablespoons in each of the 2-litre bottles.