hello, i'm new to the motorized bicycle world and i'm having a bit of trouble with my 80cc engine (Chinese engine unfortunately) I was on my way back to my house when all of a sudden the bike comes to a complete stop and the back wheel locks up. I also saw smoke coming out of the cylinder . So i tried to pedal and get the engine running again but nothing happens and its really hard to pedal when i pop the clutch. I'm not sure if the engine is seized or what but i know its not the chain getting bunched up. I can still move the bike freely when i disengage the clutch but if i try to get the engine started up it doesn't do anything, it doesn't turn over ,no kind of noise , nothing. Any idea what the problem might be?