Hi I have a problem with my rex scooter. the ride 25th then looked like the one can drive a little faster. in the black box on the left side the air comes in. then we got the stuff out there what’s in there, so that he gets some more air. there the engine was also much faster, if you gave zb gas. but faster he didn’t drive. now he made so funny noises recently and then got even slower and really rough. What can you do with it going away and driving faster again? have already installed a new battery but that didn’t do anything. I need help who can help me please? has to be out with the scooter every day.