ok, I got it. Firstly, I am not as thick as it might appear. After the post I realized that changing the tube on the machine was a silly question. Anyway, I removed the pully to get the belt off only to realize that was not required. I have the new tube in and it's holding air. I have consulted a psi chart regarding clincher motorcycle tires and have it aired accordingly. The bike is reassembled, oiled, fueled and ready...I am going to review the operation instructions and give it a go!