This Lego Technic motorcycle uses two Lego pullback motors in a V-twin configuration to power the rear wheel through a 2-speed gearbox. It's great for doing wheelies and burnouts, although it's pretty hard to ride without tipping over.
The design is elegant, minimalist and all-black. This helps keep the weight down in order for the pullback motors to be more effective. You can clearly see the exposed "cylinders" through the open frame. The gearbox works similar to the 42107: down position is 1st gear, up position is 2nd gear, neutral is in between. In 2nd gear the motorcycle has less torque but it can cover more distance.
I am submitting this to Lego Ideas because I think the use of pullback motors in a Lego Technic motorcycle is a fun, innovative idea that has not been done before. I think it would make a great candidate for an original Lego Technic set that does not require any licensing deals.