The scooter has an air-cooled lying Minarelli engine. Unfortunately, the scooter only comes to about 65 kmh, although it is registered with 80 km top speed. I have already renewed the spark plug with spark plug and ignition coil. I have also replaced the air filter, cleaned the carburettor completely and installed a new suction plug with new membrane, but the problem remained. The coming years, I got the I replaced the exhaust with the Tecnigas Silent Sport. I also installed a new variomatik from Motor force as well as a new coupling because both were worn out. I also renewed the drive belt. The belt rises in the variomatik from the very bottom to the very top as well as the converter is smooth. Due to the sports exhaust I currently drive with 5 g variomatik weights, but the scooter continues to create only 65 kmh. Mountain downhill or with tailwind are at 70 k The maximum speed of the scooter is 6500 revolutions, whereby in the vehicle certificate a power of 5 kW should be at 7500 revolutions. The carburettor should use an 86 main nozzle, at the moment a 90 main nozzle is installed because of the sport air filter mat and the distance of the snorkel. On the outer edge of the candle were slight soot deposits, whereby the electrode seemed slightly greyish. What could it be that the scooter has too little power? Unfortunately there is no indication n to the 80s scooter models. The scooter is from 1994 and related parts are unfortunately only shown for the 50 cubic centimeter model. Does it bring something to build a new cylinder set? And if so which cylinder set should I use for this? Do I have to dismantle the cylinder first and then order parts? Thank you for your help Many greetings