Good on ya! It's nice to work with someone who is willing to listen, follow directions, and give an accurate report of his findings! I've been teaching auto mechanics as an on-the-job trainer, technical school, and high school instructor for about 40 years, and it's rare to find somebody who really listens! Electrical work is the hardest subject to teach, as it's not possible to watch those electrons go about their business! Engines, transmissions, steering and brakes- - -you can see them work and figure out what's happening.
The fact that you're getting pretty noticeable voltage changes at different places in the circuit indicates you've got some loose or dirty connections to deal with, but you're in the right neighborhood to keep the battery charged now. If you want to take further discussions to email or private messages we can work out a few more details with specific suggestions for dealing with those issues. Basically, every connection from the generator to the battery needs to be clean and tight. A good ground between the regulator base and the generator housing is vitally important. Run a dedicated ground wire if one's not there already. Don't worry much about the ammeter deflection- - - -it's not a very accurate gauge, just a rough indicator of "charge" or "discharge". If you want to shop ebay for a good-quality volts-ampere tester, they're available at some pretty reasonable prices. Being able to monitor current flow with an inductive ammeter is a big help to charging system work- - - -it eliminates a lot of guesswork when just using a voltmeter. That type of meter just clamps around a conductor to monitor current flow- - - -no need to disconnect wires and put the meter in series with the circuit like we had to do 50 years ago.
Jerry
