Don't have that bicycle but I checked what I'm writing now so it works.

I used Jessi instead of bicycle (I'll call her here bicycle Jessi) - her feet worked as pedals and hip as saddle (sound weird? I know:). In the scene I put another jessi as well (New Jessi).
Now I parented left foot of New Jessi to left foot of Bicycle Jessi and right foot of New Jessi to right foot of Bicycle Jessi.
After this I selected Body of New Jessi and parented (from menu) to hip of Bicycle Jessi.
Last I applied walk to Bicycle Jessi and it worked - New Jessi followed Bicycle Jesi without any problems - feet to feet and most important hip to hip.