First of all, Pixler can be your friend:
https://pixlr.com/express/
Learn to use it and save us all from ginormous pictures. Just set the width to "640" and the height will take care of itself.
That carb is one of the "less expensive" China made models. Probably either a stock sized 24mm or 26mm. I know that it's not a 30mm carb because the stock intake manifold is still being used (which won't work with a 30mm carb). The main difference between it and the more expensive ones (approx. $125) is that yours does not have an accelerator pump to help with off-the-line acceleration.
The Uni-filter size is based on the carb venturi size, so you'll have to measure it. If I were to hazard a guess, I'd say you have a 1.5" size (Uni p/n UP-4152ST).
I'm assuming you want to know what size bore the cylinder is. No way of knowing without actually measuring it with a caliper. As far as who made it, who knows...
The cam is aftermarket, not stock. No way of telling what it is unless it has markings stamped onto it. Look for an "A9" or "A12" or something like that. I'm guessing it's an A9 (a top end performance cam) because that's what most GY6 hot rodders use.
The head appears to be stock.
And scootERIK is right, your engine appears to be missing its plastic cooling shrouds. Very important for keeping your engine cool. Without them, you risk seizing it up on hot days. If you haven't got the OEM shrouds, don't try using generic ones, they won't fit.
BTW: you can see that what you thought was a gas filter is a crankcase ventilation filter. I can see that it goes into the valve cover.
Some people can break a crowbar in a sandbox.