Engine Running Slow

Engine seems really slow, maybe hitting about 20 mph. My neighbor has a chopper bike that he fitted a bike kit into and his goes super faster than mine and screaming down the block even though he has a hairline crack in his head and other stuff going wrong with his engine. Mine should be going way faster than his. Ive probably ran about 1 gallon of gas through it and im still running 20:1 ratio, just changed the spark plug to an NGK and also my neighbor did a carb mod. What could be the problem, getting a bit frustrated :/

May not be broke in yet. when you open the throttle all the way is the carbs throttle slide going all the way open? You can check it by taking off the carb or even by taking off the airfilter and looking at the slide.
You didn't say if your engine is winding out or not and what size rear sprocket. The bigger the rear sprocket the slower it will go wide open but it will be able to climb hills. I run a 44 tooth rear on 2 of my bike and hit around 30 and one bike has a 36 tooth and will hit 40 which I think is too fast on a bicycle seeing how the bearing are made on bicycles wheels

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norms-iron-works.tripod.com

Well my engine is from BoyGoFast from Ebay, and so is my neighbors. Both mine and his are stock, but his still goes faster, but compared to his racing bike that he calls "Outlaw" it makes his chopper look like nothing, and his chopper make mine look like nothing.And the "Outlaw has that "carb mod". What do you mean by "winding". And I will take a picture of the "Carb Mod" that im talking about, basically its a tube that is extending out the carb, making it "go faster". When I get home later tonight, I will post the pictures and also see if the carb is opening all the way.

~Mac~

what I was saying winding out I'm referring to rpm's from the engine is it revving up all the way

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norms-iron-works.tripod.com

Got it all solved now. It was a defective carb that I got. Runs like a champ now, I got it all the way to 36 MPH :]
Do you guys still want to see a picture of the "carb mod"?

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Spray and pray