I've taken mine apart, governer (sp?) and all. It is tedious and scary but I was able to get it all back together with the aid of the service manual and some real simple tools.
Turns out all I needed really was to lube the governer and roller bearings with graphite. You won't need to do much more than remove several screws for this.
If it's the tension spring that regulates the governer between slow and fast shutter speeds, I think you could find a similar spring or even cut one down and make new ends with some pliers.
Graflex.org will help you much more, and the manuals are pretty easy to find online now. It's worthwhile to have your speed's focal plane shutter working. So handy, it's the major reason I use mine.