Wild thumper 4wd motors

[Sbisme offline]

Hi Gang

I am new here and new to robotics, I have just purchased a Dagu 4wd wild thumper and starting to get to grips with it, I have the Arduino controller, I have the unit connected up and working but a couple of things,
1. Two of the motors have what looks like servo wires coming from them White, yellow, red, black where do these connect to?
2. One of the motors is very lumpy when running almost like it has some sort of feedback effecting it, will this be todo with the wires on the above question?

Sorry if I sound stupid but as I say new to this so learning every step of the way,

Thanks in advance, Shaun