cam chain broken?

[Manny]

Hi everyone, working on getting my seca back on the road, but when I tried cranking it after I clean the carbs I heard some scary sounds like rocks came from bottom end of the motor. I changed the oil and filter, tried again and it started and at first it rattle and tapped then stopped, the bike stayed on and sounded good, then the low oil light came on and I turned it off and added a little more oil. When I tried to start it it rattled then just zoomed and no crank. Has this happened to anyone? Could my can chain have broken?