electric bike, motor scooter or motorbike?

when i first set eyes on this machine, i mistook it for an electric bike but then it has big tyres, so it cannot be a bicycle. then i looked around for its petrol tank. i could not see a normal petrol tank but on closer examination, the long cylindrical tube appears to be the petrol tank as there is a cover at the top of the tube.

it is a german-made 4-stroke 125 motor bike known by its name sachs madass 125.

the new generation motor bikes, especially the smaller capacity japanese bikes are so steam-lined that locating the petrol tank is a problem. the other day, i was looking at a few 125cc yamaha bikes and asking my friend to pin-point the location of the fuel tank. he said it could be concealed under the seat.