1977 Moto-Martin spine frame made for a SOHC CB750
http://img266.imageshack.us/img266/139/mm1d.jpg
http://img84.imageshack.us/img84/5063/mm2j.jpg
http://img825.imageshack.us/img825/2359/mm3e.jpg
http://img843.imageshack.us/img843/7534/mm4n.jpg