If they're 3 yellow wires they are the 3 phase AC circuit that feeds the Regulator. They first go to a junction point that ties them in with the wire harness up under the front "Hood" area of the 450R. The best and easiest way to see or get to them is by removing the right front fender (if you're sitting on quad it's the right hand fender).
The other plug should have also 3 wires.
Wire is Black (with a Red Stripe), 1 Blue wire and 1 White Wire 1 Green Wire (with a White Stripe), and 1 Blue with Yellow Stripe.