Clarence - I can't tell for sure, but I think your Cirkut back may be a fan drive, rather than a governor drive. Look on the back and see if there is a flat lever which moves to different marked speeds - 1/2 through about 1/12 (I'm doing this from memory, which is none too good). If there isn't a speed selector, and there is a shaft or two poking out of the bottom of the back (can't see from the pics), then it is a fan governor control. This means you need to make a set of fans, in addition to needing gears. Maybe Jamie has a pic of the fans. Fans should be way easier to make than gears.
eBay #110239245018 shows the bottom of a fan governor Attachment. I suspect your looks like this.