Yesterday I added the 20cc oil, so there is 100cc in total. Now it works well with enough damping power. If somebody wants to do the same job, i found out that the easiest way is to add the oil from the bottom. The upper plug was so stuck, that i could not remove it.
Now my People is almost ready. Next week the Metzeler front tire will be installed and new brakepads. The original speedometer had got water in it because of the missing computer rubberknob. I installed a new mechanical counter from a Baotian scooter.
The reason why the the motor had seized was the oilpump sprocket, that had lost 12 teeth. Connecting rod and piston were broken.
Now it has has 47mm piston and cylinder and all other moving parts and camchain etc. Maybe it has been ridden 15000 km on it, because there was original 2006 year tire in front. Now this People S 50 will start its new life in Vaasa, Finland.