Markus:
Cut the fins off the flywheel. Mount the prop hub to the flywheel. Much shorter to cut off the rear shaft, or leave it on if you intend to put a starter on it. XL 12 is 55 cc. Gasser has roughly 3/4 the power of an alky burner but open to controversy. If I remember right, clutch should screw off clockwise. Have fun.