where do i put engine oil in peugeot speedfight 2. ?

I take it when you say engine oil you mean two stroke oil? The two stroke oil tank is usually found beside the petrol tank, it will have a rubber oil tank cap on it which you pull off. Fill the tank with two stroke oil, when the tank is full, you push the cap back onto the tank.
I'd be a bit concerned if you let the scoot run outta oil.

steo
July 2009