As amusing as it is I think this says more for the flaws of Box2D's accuracy than a global conspiracy
At first I assumed that the machine worked simply because you set a value of 0 for friction in your weighted wheel (I can't see how it's unbalanced though, there's no weight distribution) , I'll admit that I have yet to break it -at a guess I'd say due to the non-deterministic nature of the physics engine and elasticity of objects; but perpetual motion itself is a myth at best and hoax at worst.
Still, great experiment! I'm stumped
even if you make astronomical friction or density! you will still have the movement! i even added the linear damping and angle damping is the "perpetuum movement" is still there in this example!
i tryed to create da vincy`s perpetuum wheel! that 1 seems to act more realisticly and eventually stops! now im tryng to tweak the graphics and see if i can make it perpetuum! BTW all wheels have weight! the diference is the big one is double in weight then the smaller once! but even if you make it small in size or weight will still turn! so the physics arent real enough i think !