1. Through the oil filler plug:
- Locate the oil filler plug, which is usually on the right side of the engine, near the top.
- Remove the oil filler plug.
- Use a funnel to add oil to the engine. The recommended oil capacity for the 1980 Honda Goldwing 1100 Interstate is 4.5 quarts (with a filter change) or 4 quarts (without a filter change).
- Replace the oil filler plug.
2. Through the oil drain plug:
- Locate the oil drain plug, which is usually on the bottom of the engine.
- Place an oil pan under the oil drain plug.
- Remove the oil drain plug.
- Allow the oil to drain completely from the engine.
- Replace the oil drain plug.
- Add oil to the engine through the oil filler plug, as described in step 1 above.
