I recently purchased a Singer 127 treadle. I followed Billy's advice and got her all cleaned up and just got the belt today. I installed the belt, but now can't lower the head into the cabinet to close it. Do I have to take the belt off to do so? If so, how?

There is a small lever that the belt goes through on the wheel below. You push the lever until the belt comes off. Not a big deal!

Thanks so much! I was just pushing on that lever. I needed to operate the treadle at the same time. Appreciate your help. Can't wait to sew on her.