To answer your question as to where did I learn that, I did all of the above in a class in high school.
Similar with lawnmowers, the market is mostly electric now.
I would have thought with the replacement of gas powered lawnmower type engines with electric that it would be easy to find a used 5hp Briggs and Stratton to overhaul. A lot of the commercial landscapers around here still use gas powered tools.
The Holley (or Carter) carburetors were pretty easy to find on eBay. Some that looked like they would need a rebuild kit seemed rather inexpensive, in the $50 dollar range.
Looking at the prices of the Datsun Z-Series, wish I kept mine. Who knew they would rise in value so much! I think I paid $2000.00 for a used one in great condition back in the day. They are an absolute blast to drive!
This thread has me wanting to pick up a project truck from the 50s or 60s. Fun hobby, brings back memories of when I worked on restoring cars at Barrett Jackson.
I would start with some easier procedures to get your confidence up, like maybe a valve cover gasket replacement or a serpentine belt replacement. Then move on to harder things.
Also, if you live in a rust-prone area (and you are using simple hand tools), your most important items will be penetrating oil, a big breaker bar, and a large sledgehammer. :) Getting rusty things unstuck is kind of an art in and of itself.
Some good learning resources:
- Honda Common Service Manual (general motorcycle repair)
- Haynes, Clymer, or official service data for your vehicle
- ChrisFix on YouTube
- Revzilla's The Shop Manual (and its precursor, Motorcyclist's MC Garage)
- The forum or subreddit for your vehicle
Get something cheap to learn on at first, before spending the time and money on a "classic". Something fairly common, so you can find info on repair online (forums/youtube). Get a Haynes workshop manual for it.
Make sure you have access to a garage space with a lift.