Is there a rule (and if there is which page of the rule book) that explains that you can not heal these characters past there respective 100 point dials at the begining of the game with say.... Characters with support?

Ie

300 point game I take...
200 point black Adam and the atom

Can I heal the Adam to his 300 point range of abilities?

A character's starting line is the point at which he cannot be healed. It used to say 'green starting line', but due to multiple starting lines they changed it to wherever you paid for. This has been a rule since the olden days of the original Sentinel. The only difference now is how often it shows up.

2011 Core Rule Book page 10:

HEALING
Characters can have their damage healed through the use of powers like Regeneration, Steal Energy, and Support, as well as through other game effects. When a character is healed of damage, turn its combat dial counterclockwise a number of times equal to the damage healed. A character can’t heal beyond its starting line.

Awesome thanks. I just needed to know where in the rule book it said that

There's also this helpful text from the Player's Guide, page 4:

Some characters have red, blue, and/or yellow starting lines instead of a green starting line. These characters may also have different point values and experience levels listed on their base/character card. Use the starting line that matches the color of the point value or experience level.

so I guess this would also apply to 057 superman's special ability?

"Superman Returned once per game, when Superman would be KO'd, instead heal him to click #6 and modify his combat values by +1 for the rest of the game. When this happens, he counts as KO'd for traits named "reign of the Supermen"

No. His starting line is click # 1. When he is 'Returned' he is simply healed to click #6, but he can still be healed back to click #1 after that.

As W.I.T. said that isn't an issue. Think of figures like GSX Phoenix who would "return" after dying or other devices such as the Lazarus Pit. Heal away brotha!

Back to the original poster's question not only does this apply to figures with multiple starting cost but it also applies to figures who have the AE mechanic.