Go to Autozones website, look up the alternator that you have, probably '95 Geo Metro. There is a diagram there that shows what the pins are for. The ignition pin is the exciter. The lamp pin can be used for an idiot light by connecting it to one side of a light and connecting the other side of the light to another positive power source. I used 12 gauge wire for the output and connected it to the battery side of the starter solenoid. 10 or 12 gauge is fine, compare that to the size of a wire inside of a 50 amp fuse or the size of a 30 amp dog bone fuse.
Picture those terminals making an upside down U , the terminal on the left is the ignition terminal, the terminal on top is a dummy, the terminal on the right is the lamp terminal.
First I want to thank you guys for putting me on the right track. I looked at a 10 gauge and thought it was too big. the parts store has red 10 gauge with hook ups on both ends, six dollars. you cant beat that with a switch.
I connected the charging wire to the battery side of the starter solenoid because I don't like a stack of terminals on the battery. I didn't use any fuse. The bike is protected by the main fuse at the solenoid. Batteries and alternators aren't usually fused anyways.
You can connect the charging wire to the battery or the solenoid, either works.
I also added a ground wire from a screw on the alternator body to a bolt on the bike frame that holds the bracket for the rectifier/regulator. There are other wires grounded there also. It would be awful chasing down an electrical problem in the future that might be caused by a bad ground at the alternator.
For the ignition wire we used the blue wire at the stock regulators connector. Run it to the plug on the back of the alternator. There are two terminals at that plug on the alternator. One goes to the blue wire and the other was for a idiot light that would be in the dash of a car telling you that something is wrong in the charging system. We also used a #8 wire to the battery with a 50 amp circuit breaker in line. Good luck. You will not be sorry you went this route.