Mick bought the bike new back in 1975 but now there is not much left from the original CB750, maybe a few bolts, as Mick says in the video. Everything was changed and rebuilt. This beast has got some parts from different models and Rickman frame. Although it took a significant amount of time and energy to get there it's totally worth it.
When the bike had been already built and constructed (and it was a big 4-cylinders motorcycle) Mick started thinking about things he could do to make it even more impressive and fun to ride, that's when he came up with a Supercharger idea. He got his kit from Switzerland.
Surprisingly, according to Mick this Honda CB750 Cafe Racer is very comfortable to ride, a little bit low on the handlebars, he says, but still comfortable.