Here's why:
* AR codes are not designed for specific encounters: AR codes in Pokemon HeartGold are used to unlock specific events, items, or even Pokemon. However, they don't manipulate the game's code to guarantee shinies.
* Shiny rates are predetermined: The chance of encountering a shiny Pokemon is already programmed into the game. It's a low probability, but it's not influenced by AR codes.
Tips for finding shiny legendaries:
1. Save before encounters: Before engaging with the legendary beasts, save your game. This allows you to reset the encounter if it's not shiny.
2. Repel spam: Using repels can be a good strategy, as they prevent other Pokemon from appearing, increasing your chances of encountering the legendary beast.
3. Masuda method: If you have access to another Pokemon game version (SoulSilver in this case), breeding Pokemon from different regions can significantly increase your chances of finding a shiny.
4. Patience and luck: Finding a shiny Pokemon is primarily a matter of luck. The more times you encounter a Pokemon, the higher your chance of finding a shiny.
Remember, there's no guaranteed way to find a shiny Pokemon. Be patient, persistent, and enjoy the thrill of the hunt!