Hey there! I have a Cimatti city n=bike and hasve the same problem. (did) I chanfged the plug make sure the plug gap is good. You can get a kit for it depending on the type of bike you have. What do you have? You can get a performance upgraded kit to make a 65-70 cc kit to make it faster. I am in Vancouver Canada, and order the parts threw Steve's Moped in New Jersey. 1.201.384.7777. give me you email and I will keep in touch in case I need help too. I am working on getting an exhaust custom made for the bike. As you know or may not.. the 2 stroke engine thrives on exhaust therefore the one thing that should be modified is that. It will cost a few bucks, BUT it will increase hp from say for ex.. 30 mph to 55-60 mph. ow THAT is worth the money, do you think? Anyway I will await for your e-mail and talk to you later.