Interesting that the Cub has what looks like a 12 volt generator, the same size and style as the original Cub 6 volt generator.
The gen in your pic has an ID plate with red paint, which Delco, the maker, used to show it is 12 volts.
The 6 volt gens and starters had plates with black paint where the red is on the gen in the pic.
Please write down the model number of the gen and post it here so we know what it is. Googling the number will probably tell what voltage the gen is. Then we can be sure of the voltage.
The model number is the left number on the plate. It is probably 7 numbers.
There is probably a serial number on the right of the plate, it is probably 4 numbers, I don't need that.
You could write down the model number from the starter also, and post it on here. It is in the same place on the plate as the gen number. Sometimes the paint is worn off the plate, I don't see any left on the starter plate.
The starter looks like an original Cub 6 volt starter, but the removeable band at the end of it is different.
People on here commonly use a 6 volt starter when they convert a Cub to 12 volts.
Below is a page from the 1950 Cub owner's manual, showing the electrical system parts, with the hood off.
http://farmallcub.com/rudi_cub/www.clea ... e%2033.jpg
Yours has a different unit on top of the gen than the 6 volt gen in the pic had.
It looks like it is a voltage regulator, like was said before.
The pic has a Relay on top of the gen, the voltage regulator was used on Cubs after the Relay.
The voltage regulator regulates how much power the gen makes, to charge the battery.
The magneto originally is not connected to battery power, it makes it's own power, as it is turned by the engine.
Don't connect it to battery power, if it is using the original magneto coil.
The coil wire in your pic is connected to the top cover post on the magneto.
That is where the original magneto coil is, at the top of the magneto, built in the magneto.
The magneto needs no converting to 12 volts, if you are using the original coil.
There is no separate, round cylinder shaped coil, like cars used.
It is easy to set the gap of the magneto points.
I sit down on a lawn chair or something, next to the engine. It is easier working on the magneto.
In your pics the magneto is assembled. Before removing the cover over the points, turn the engine so the rotor is pointing straight up, that is where the number 1 cylinder spark plug wire post originally is on the cap. This will help you to not lose the timing when the cover is off.
Number 1 cylinder is used as a reference for timing.
In the pic in my post on page 1 of this post, you can see there is an oblong shape on the magneto center shaft, in near the points, that is the cam that turns and open and closes the point on the right, or lower side.
The cam has 2 areas that are high.
The right point has to be to the right as far as it will go to set the point opening.
There is a part of the right point that rubs on the cam.
While the hood is off, I would oil the generator oil cups.
There is 1 at the front, and 1 at the rear.
Open the top of the front one, and put in 5 or so drops of thin motor oil from an oil can.
The rear oil cup's top is gone. It was originally like the front oil cup.
If it has dirt in it, from no top, try to clean it with a small screwdriver and a rag.
If you can't set the point gap, you could try to find someone that knows how, and have him do it, and show you how.
I hope this helps.
. I do notice in this forum that people have a lot of different names for the same thing. 
