Could be in need of a tune up.
The main cause of motorbike smoke is when the diesel is being burned and used in the engine. This smoke causes pollution to the environment.
Could be time for a tune up, spark plugs, wires, etc.
It is the alternator....
Lack of propulsion.
dirty fuel filter
Burning rubber, or screeching the tires, and then accelerating.
The most common cause is slipping belt
Bad ignition coil
unburnt fuel
Cylinder miss.
you have a vacuum leak