Rinse pork strips and drain well. Pat dry.
In a large bowl, combine 7-up, soy sauce, vinegar, 1 cup of the oyster sauce, brown sugar, garlic, black pepper, and chili peppers.
Add pork and massage meat to fully incorporate. Marinate, turning meat once or twice, in the refrigerator for at least 4 hours or overnight for best results.
Thread 2 to 3 meat slices onto each skewer.
In a bowl, combine remaining 1 cup of oyster sauce, banana ketchup, and sesame oil. Set aside.
Grill meat kebabs over hot coals for about 2 to 3 minutes each side.
When pork starts to lose its pink, baste with oyster sauce-ketchup mixture. Continue to grill and baste, turning on sides, until meat is cooked through. Remove from heat and serve as is or with spicy vinegar dip.