I have a scooter with the battery disconnected for the winter. I have no experience with this, and I forgot how the wiring were before. I tried to look online, almost every place said there should be a red and a black wire, positive and negative respectively; and if there is a third smaller one, that should go with the positive.
The problem is there are indeed three wires, two thicker and a thinner one, but the colors are black and blue for the thick ones, and red/blue for the thin. I also read it can ruin the bike if I connect it the wrong way... How should I connect this up without having any tools to measure? This is an italian bike, if that helps with anything.