Well I don't think you could be called a beginner, Sorry,:ashamed:
I just got that feeling watching the video.
My last bike was a DR500, suzuki, on off road. was a little heavy for me in the woods. I had a Yamaha yz 490 for a short while, that thing was not my style and was scary to ride. I prefer trail/woods riding. I also had 2 husqvarna's, a 250 and a 390. A Bultaco, that came closest to serious off road riding, not a trial bike but would go thru anything. Many others bikes as well.
My most interesting bike, that got the most attention was a Susuki GT 750.
A water cooled, 3 cylinder, 2 stroke street bike. I got my first one when I was 16. (had 2 of them) They use to call them the water buffalo, cause water cooled bikes in 1978 where rare. It was a fast bike for the times, but had a detuned 3 into 2 exhaust system. I put 3 expansion chamber pipes and carb jets on it and it was totally insane. sounded like 3 separate 250's going down the road.
Also insanely load, had to take them off cause the local PD had enough of it.
That is some collection you have there, wouldn't doubt it if you don't have a GT in there. They also made a 550 air cooled 2 stroke, with a big scoop on top of the engine.
JB.