Re: Motor Refuses to start
I have included a few pics to help you understand. The key is less than a 1/2 inch long, it's just a tiny little "key" that slides into the keyways so that the flywheel (the "thing" you want to remove) slides onto the shaft (which also has a keyway).You may notice that the keyway is damaged in the second pic.
The first and forth pic is what you want to remove, but keep in mind that these are not pics of our motors.
Another way you can remove your flywheel is to follow bikerguys advice but I will add this: make sure you wind the nut onto the shaft until the face of the nut is even with the head of the shaft. This is so that you do not mushroom the shaft as you hit it with a hammer. With your left hand, hold onto the flywheel so that you are holding the whole bike up so that as you tap the nut, the weight of the engine helps you in removing the flywheel. His wood idea is doing the same thing as it is putting pressure upwards,sort of pushing outwards. The reason the flywheel seems stuck is because the shafts are tapered (cone shaped). As the parts are tightened up the shaft tighten up on themselves. You are trying to give it a good shot with the hammer so that the shock breaks it loose. You could also try to find a "puller" as this is what they are made for.