I once had a 1972 Yamaha 200cc 2 stroke, which was used for school and some long rides. It is very simular to the DS-7 except my model had the exhaust mounted higher up, almost right under the seat, if I recall correctly. It also ahd a oil tank mounted on the right side (i think) and had a site window to let me know when I was running low on 2 cycle oil. Can anyone tell me the model?