How did this builder solve the drivetrain on a CZ 175 with a Lada Samara 1.3 engine?

I came across this wild project on YouTube — a CZ 175 motorcycle fitted with a Lada Samara 1.3L engine.
Here’s the video: https://www.youtube.com/watch?v=x6H85GhCetw

I’m really curious about the drivetrain setup.
Does anyone know how the creator managed to transfer power from a car engine to the rear motorcycle wheel?
Was it a custom gearbox adaptation, chain conversion, jackshaft, or something else entirely?

Also, if you’ve seen similar engine‑swap motorcycle builds on YouTube (especially ones using small car engines with chain drive conversions), I’d love to check them out.

Any insights, guesses, or links to comparable projects would be super helpful!