Yes, I had a Honda cub and it has a four speed transmission and a chain drives the wheels. Put the tranny on neutral... turn ignition to "on" position... push the bike... shift to second gear... engine will start... it's that easy.... In a scooter, it's totally different...(except for some with wet clutches)
Didnt you notice that when going down hill with the engine on, no matter how fast, the engine is still idling? This is because the wheels are turning and the clutch is not engaged.... give it some gas and the scoot will engine brake and lock the rear wheel,,, this means that when you gave gas the engine turned and engaged the clutch...
In your next question... at 160 kph, my theory is that it might turn the clutch, the engine might run, then the engine speed might not match the bike's speed, things may go out of control, you might crash and die... my two cents..