Even if you leave Johto Entei and raikou will still be there.
You cannot catch Raikou in Pokemon Black. You have to transfer it from Diamond, Pearl, Platinum, Heartgold, or Soulsilver.
he roams the map after you beat the game
Pokemon HeartGold and SoulSilver.
You cannot catch Raikou in Pokemon Diamond and Pearl. To get Raikou in Pokemon Diamond and Pearl, you must trade for one from Pokemon HeartGold and SoulSilver where it can be caught or transferring from Pokemon FireRed and LeafGreen.
You will have to either trade for Raikou or transfer from Diamond, Pearl, Platinum, HeartGold, or SoulSilver.
You can get it in Pokemon heartgold up the belltower ( but make sure you have a lv. 100 raikou
The best electric type Pokemon can be ether a Raikou or an Ampharos, I hope this helps.
you can get raikou in the grass. trust me i am 100% sure [all over johto]
It means you have not seen it, but if you have you should also see Entei n the map, if you see Entei but not Raikou it means that Raikou is currently on the same route as you.
In Pokemon Heartgold Raikou and Entei are roaming around the region, while Suicune awaits you to come across its path before running off, and waiting for you once more.
Well why don't you stop playing RED and play HEARTGOLD OR SOULSiLVER it is a lot easier
kyogre moltres zapdos articuno lugia ho-oh groudon scuicune entei and raikou