I recently bought a 1977 Cimatti City Bike that was not working when I bought it. This is my fist moped and I have been reading up. Frist, I cleaned the gas tank with Kreem and I bought a new fuel valve, new spark plug, fuel filter and checked the fuel line. It started after that and ran, but really crappy and slow. So, I read some more and cleaned the carb, checked the exhaust, checked to see there was spark and that it was getting fuel and checked the compression, which is about 110. Now it won't even start. There is a lot of black fuel or something comming out of the exhuast and getting on the spark plug. I have read Fred's Guide and it was helpful and I have searched on this forum but I am out of ideas. Any thoughts?