Hello guys, I bought a 17-year-old MBK Evolis with now almost 8000 KM untunt.I have now changed almost all wear parts.At “Zweitaktfreunde.org” I read that one should change/check a membrane after 5 years or 10000 KM.What do you think about it? I would like to drive the scooter for a long time, but I’m not sure if I should change the membrane.Is everything still original equipped with the two “tipped-off screws”. or will the material only become soft and the membrane leaks, which is why one notices in the company? Traditionally by the professionals here in the forum help!!! MfG Bernd