Pull up on the upper sprocket and chain while you roll the crank pulley backwards(counter clockwise) 90 degrees and see if the chain get's suddenly longer on the driver's side.

It will drop down on that side and kink just under the crank gear when you remove the upper gear and allow it to rest on the chain guides.

There is a shallow ridge cast into the t-cover that is supposed to prevent the chain from sagging off the gear there, but it can get worn down if the chain was ever too loose or broke in operation.

Make sure to keep tension up on the chain/sprocket as you return the crank pully to 0.