I have had for years a two stroke cylinder sitting on my shelf as a book end and I have no idea what it is for. Here are the dimensions Bore is 67mm stroke is about 70mm so that would make it around 250cc. The exhaust port is 49mm x 18mm. Spark plug thread is 18mm. The base bolts are 77mm apart. Can anyone identify this cylinder it might be of American manufacture. See pictures