Personal motivations are definitely are a part of what defines a heroic character. If it's done for selfless reasons to benefit another without any rewards, the individual can be considered heroic. However, if done for selfish purposes, that can't be considered heroic.
It's true - I've done a lot of deeds for people without expecting anything in return. I've been praised a few times for it but that wasn't the primary reason I chose to do anything.