A rider reports that the motorcycle creeps forward even with the clutch lever pulled in and the gear engaged. What is this symptom called, and what commonly causes it?

1. Clutch dragging, often caused by excessive cable free play, warped plates, or thick/incorrect oil preventing full clutch disengagement
2. Clutch slipping, caused by a fully charged battery
3. Brake fade, caused by worn tyres
4. Engine knocking, caused by a clogged air filter