Make shallow crosswise slits in the meat of the chicken parts to help absorb more flavor. Mix together the lemon juice and meat tenderizer; rub into the chicken meat. Place chicken into a shallow dish.
Place 1/2 cup yogurt, cumin, coriander, cilantro, paprika, turmeric, salt, pepper, and garlic into a blender or food processor, and blend until smooth. Transfer to a bowl, and stir in remaining 1 1/2 cups of yogurt. Pour over the chicken parts, cover, and marinate in the refrigerator for at least 8 hours, or overnight.
Preheat grill for medium heat.
Lightly oil the grill grate. Remove chicken from the marinade, and discard any remaining marinade. Grill chicken 30 to 45 minutes, turning frequently to prevent burning, until juices run clear. Smaller pieces will finish cooking first.