Converting your Ford 9N from a 6-volt to a 12-volt electrical system assures that the battery will be charged by the generator when the tractor is idling, something a 6-volt system cannot do. The conversion will eliminate cold start problems. For the 6-volt system, hard cold starts are a notorious issue. Parts will be much easier to find for your 12-volt system, because the 12-volt system has been the industry standard since the 1950s.
Detach the negative cable from its terminal on the battery. It is easiest with a socket on the nut and a wrench on the bolt. Do the same for the positive cable.
Remove the screws attaching the battery cable to the 6-volt generator. Un-thread the regulator wires from the generator with a screwdriver. Unscrew the wires from the regulator.
Remove the battery from the 6-volt battery mount cage with a wrench. Do the same for the generator and the regulator. Grind the three mounts off the frame. Weld the 12-volt battery, alternator and regulator mounts to the frame. If the 12-volt regulator is attached to the alternator, there is no need for a regulator mount.
Remove the light covers from the light housings with a screw driver. With needle nose pliers, remove the 6-volt lights from the light assemblies. Remove the 6-volt assemblies with your screwdriver. Mount the 12-volt assemblies with a screwdriver. Seat your 12-volt bulbs. Replace the light covers.
Cage the battery in the mount with the original wing nuts. Bolt the alternator and regulator to their mounts with your socket set. Screw the regulator wires to the alternator and the regulator. Screw the battery cables to the alternator. Attach the battery cables to the terminals of the battery. Connect the ballast resister to the coil if your tractor has an electrical ignition.