Is asking for comments to much to ask?

I'm not sure if this is something that happens to everyone but it seems to happen to me. Whenever I ask for feedback on a story i don't usually get any response. While I know that i have loyal readers, who I am very thankful for, I've only ever gotten a handful of comments. And while that's great whenever I ask for more with the reward being another update...nothing. Am I being too pushy? Is there a maximum or minimum number I should be asking for? I don't want to seem like I'm nagging for comments so what I want to know is... is asking for comments too much?