Describe the four wires you mention. State whether or not they were actually attached to the mounting cradle. State whether or not the original battery has any wires coming from it at all. Describe the relative thickness of the red and black pair, and the other pair. Describe whether or not the other pair, and the red and black, are enclosed in modular connectors or are bare wires.
Describe how and when you obtained the diamondback. Describe if anyone has done any work or repair on this bike. Do you know who actually made it? I do.
I have done the research you should have done. I KNOW some of the answers to the questions posed. I do not believe you are telling the full story, which if you had would have saved a lot of time and effort. I have put in that time and effort to help you solve your problem. I know what the other wires are NOT, and also what they could be. I know SOME of what you have failed to mention.
This is not my first rodeo. I get tired of playing 20 questions. You have left out important details.