Workflow for managing pull requests on shared repos in github

I'm trying to manage a pull request on a repo that I don't own but have admin rights on. When I attempt to pull in changes from another fork, it fails with an error that is less than clear. Here is my workflow...

1. Fork main repo
2. Make changes in that fork
3. Commit to that fork
   3.5 (goto step 2)
4. Submit a pull request to the main repo

As an administrator of the main repo, I'm attempting to merge those changes as follows...

1. git clone git@github.com:dude/project.git
2. git checkout -b gtracy-master master
3. git pull http://gtracy@github.com/gtracy/project.git master

After entering my password, I get the error message...

error: The requested URL returned error: 401 while accessing 
http://gtracy@github.com/gtracy/project.git/ifno/refs

Is this workflow wrong? Is there an easier way to manage my own pull requests?

Thanks!