Marcello with the bike he's building in the comic. It's based on a 1914 Cyclone board track racer, with modified frame and updated wheels/tires/forks. In the comic, he's commissioned a custom engine based loosely on the Cyclone design, but with modern internals, much higher compression ratio, updated combustion chamber design etc.

Quick cleanup of a rough sketch. The bike is sketched over a 3d model I made of the bike. From here on, I'll be freehanding over this so it keeps a hand-drawn look.