Place chicken in medium size bowl, add 1 cup of vinegar and marinade for atleast 1 hour at room temperature.
Meanwhile, melt the butter in a small frying pan and add the onion and garlic, and saute until tender for about 3 minutes. Transfer the onion and garlic to a medium sized saucepan. Place the pan over medium heat, stir in the orange juice, honey and ½ cup of vinegar and bring it to a boil. Reduce the heat and simmer stirring occasionally for 10 minutes. Remove from heat and refrigerate to allow the sauce to cool and thicken.
Remove the chicken from the vinegar marinade and reserve the marinade. Sprinkle both sides of the chicken with salt, black pepper and red chilli powder.
Light a grill. Place the chicken on the grill, skin side up and cook it over medium direct heat for 20 minutes turning and basting frequently with honey, garlic and salt.