Engine seized up!

Hi! I rode for about half an hour before my bike suddenly stop going with engine still revving. It appears that the chain is locked and seized up with the motor since the rear wheel still turns? Did the chain get stuck inside the engine or something much worst? I just missed my class because I had to bike the rest of the way to school. Also, the plate on the rear wheel, (clutch plate?) is loose in that it can be moved a little bit wheel clutch is disengaged, is that normal? Thanks!

-newbie

Chinese motor.

The chain is stuck in the motor. It can run but the chain can't move since the motor ran, just couldnt move the chain. The chain actually came off when it seized up so maybe the chain did not have enough tension and it jumped or got stuck in the motor housing? I can't check right now because I don't have tools with me.

Thanks for tip. I'm glad I wasn't on a busy narrow street. I had to tie the chain with my scarf to the rear rack so I could pedal to school...