I wouldn't think eating beans would have any effect. You can basically eat anything, even things that give you gas or very spicy foods and it shouldn't effect baby, unless there's an allergy or intolerance, as you know.
As a friend once put it....the beans aren't going directly through your breasts into the baby....your body is digesting them, breaking them down, getting the nutrients from them and the other food you eat...and making breastmilk.
I was dairy-, wheat- and nut-free for 18 months after having my second child due to his intolerances. I practically lived on beans! I'd eat black beans and rice, vegetarian chili, etc. He was fine.