Combine the sugar, flour, cinnamon,salt and lemon zest in a small bowl.
Mix the Pear and Pineapple with the juice from 1 Lemon and place 1/2 of the mixture into the pie crust. Sprinkle 1/2 of the flour mixture over the fruit. Add the rest of the fruit mixture and sprinkle the rest of the flour mixture on top. Pat the filling down a bit to make it firm.
Thinly shave the butter and place randomly around the top of the pie filling. Cover the pie with second crust, press the sides together with a fork and cut a slit in the top of the crust.
Bake at 450 degrees for 10 minutes then cover crust with foil and bake at 350 degrees for 30 minutes.
Uncover crust and bake an additional 10-15 minutes until crust in golden brown. Remove pie and let it cool for 45 minutes on cooling rack.