It seems that we cant get into your thick head You make it sound way too simple. You cant just build an engine and it will work, you NEED R&D.

But all of these parts are critical to the proper function of the engine. Lets take TopGun's engines. He makes it seem, to any person who doesnt know him too good, like he is just the average hobbiest who built his engine. But he isnt, he has decades of expirience in 2 stroke engine desingn, operation and modifying. He allready has 50% of the equation, the other 50% is manufacturing. (theres adds and money, but we wont get into that).

You are taking these 2 parts of engine production and generalising them, like everybody and their brother could do it tomorrow. You need years of working in any of these 2 areas before you can even think of making any device, let alone an engine.

Like I said in my other post, we dont live in a perfect world.