I hope someone can help me further is desperate and I’m running out of ideas. I have a Rivero VR50 2T 50ccm built in 2010. The scooter does not get petrol it does not build up a vacuum on the carburettor. I have replaced the gasoline pump, gasoline filter, Simmerring cylinders & pistons, intake nozzle new air filter ect. Between intake nozzles and membrane I have lubricated silicone seal that can withstand high temperatures quite easily. All 4 light when I blow pure and are also all tight. When I suck at the vacuum hose petrol comes but if I try it by E starter/kick starter nothing does. The compression is very good. Echoke tested on the battery the needle moves. With brake cleaner in the carburettor then the scooter jumps immediately and then goes out again.