North's move was motivated by the desire to win more silverware - something he achieved when Saints defeated bath in the Challenge Cup last Friday.
But he is well aware that if his side are going to be crowned champions then they will need to pull out all the stops to overcome Saracens at Twickenham.
"It was gutting to watch how Saints lost the final last season, but it's a new game this year, it's a whole new team that we are playing against in the final," said North.
"They've consistently been the best performing team in the league and we can't expect anything less than 100 per cent from them at the weekend.
"They lost out on some silverware last week but they've got another chance to win something before the end of the season.
"It's Premiership final weekend and we can't leave anything out on the track. You've got to go full fat milk - flat out and as hard as you can - you only get one chance with a cup final."