There's the airhead engine itself, the star of the show, with an appropriate amount of airspace between it and the rest of the bike. The curve of the frame at the rear wheel, the sweep of the exhaust pipes, the prominent upright rear shocks ... it's all delicious, and all somehow rendered in block form. There's even a hand brake. And of course, would it be a proper Lego Ideas proposal without a Stormtrooper riding it in one of the photos? This one nails it.
Even better, it's builder, maximecheng03, is working on a sidecar, which will hopefully be a period-correct Steib. Given the builder's attention to detail, we expect the car to be almost as delightful as the bike itself. If you like the model, you know what to do: vote, and make it happen as an official Lego kit.