Ok I have worked and owned on hobbits before. I also had the same problems that you were having. Ok first you should clean your exhaust or get a new one. Then just remove the air filter and the plastic tube holding it in. This will not hurt the engine b/c they have a huge jet in the carb. Make sure the brakes are not dragging and the tires are pumped up. A new sparkplug will also help a little. Make sure your drive belt is tightened. If you do this I am positive your hobbit will gain speed.