The engine seems to be a 110hp 7 cylinder radial from Rotec Engineering. The bike from the notorious Jesse James’ West Coast Choppers. 110 Hp, more than enough to fly an aeroplane.
In my opinion this is actually Diesel Punk rather than Steam Punk. Why? Because it’s an internal combustion engine and not a steam engine.
Very Steampunk. Bet he’s glad of the mask with the chill wind blowing past his phizog. I once arrived at work after a wintery motor bike ride with my eyelids frozen open.
From 22zddr on DeviantArt
Dieselpunk a la Jean Paul Gaultier
Trainspotting - by Strangeknowledge
Thanks to Hilde for the link!