Originally Posted by Ironfish653

Nope, it'd go in a straight line.
Ex-pro moto racer, writer, and rider coach Keith Code has a demonstrator at his California Superbike School called the "No BS (Body Steering) Bike", which has a second, fixed set of handlebars. Students are instructed to try to make the bike turn using only the fixed bars: The result is that no amount of throwing your weight, pushing up or down, makes the bike turn (the wheel is still free, it just goes in a straight line)
While his philosophy is the subject of debate in moto circles, the bike proves that you have to have some sort of controlled, purposeful steering input into the handlebars, in order to make the bike turn. On a velo, those inputs are slight to the point of imperceptible, unless you're really focusing on it, but on a heavy moto at medium speeds, it requires a much more deliberate and noticieable action.