In a medium bowl, combine the turkey, bread crumbs, chopped scallions and 1 tablespoon soy sauce. Form into 16 meatballs; transfer to a large plate and sprinkle with the sesame seeds.
In a small bowl, whisk together the remaining 3 tablespoons soy sauce, the lemon-lime soda, sesame oil, ginger and garlic powder. Transfer half of the mixture to another small bowl for serving.
Preheat the grill to medium. Thread the turkey meatballs, scallion pieces and Asian pear wedges onto skewers. Grill, turning occasionally and basting with the soy mixture, until the kebabs are browned, 10 to 12 minutes. Serve with the reserved sauce for dipping.