I have an 80cc 2 stroke bike engine made in china, and I have a great curiosity as to why when i reach top speed it feels like my engine has a governor on it??? I just got through my first 2 gallons of gas (4 1/2 gallon tanks) and my manual says that my break in is done. I just tried to hit full speed today and when i did, i got it up to 34 MPH but was only able to hold it for maybe about 2 seconds before It sputtered back down to 30 MPH. What causes this? How can i better my top speed without risking hurting my engine and still keeping gas mileage up? Right now i have an average of about 80 miles to a tank. Does anyone have a shifter kit that they have a picture or movie demonstration of? If not Can someone that has one make a youtube video so i can see how it works and if it is really worth dropping on my 30 year old Univega? thanks guys i know you will be of great help if you respond to my post!!!!