Pkmn SS tips on catching Raikou?

I want to catch raikou. I caught entei easily but raikou is causeing me way too much trouble not to get in to details but I spent like 200thou pkmn cash on ultra balls and max repels( so I don't run in unnecessary battles) I burned him have have like 12 hp left on him but still breaks out the ball I need help on catching him. Tips or techniques