Well, my bike goes 41 MPH, according to my Garmin strapped to the gas tank. Iv'e made several runs and always got close results. This is with a 36 tooth and a lot of work, open header exhaust, Duane's GT50R carb (tuned), Manic Intake, etc. I went 35 with my 44 tooth which I miss a little because I had a lot of pull on low end. I lost that with the 36 but I ride to get places and I want to keep up with traffic as much as I can. I have pics on my phone, if people really care, I'll see if I can post them up (If I still have them, my memory got full a couple times so I deleted some) But 47 smells a little fishy. Maybe with that small sprocket I think he mentioned, down hill. But 44 MPH flat with that small of a sprocket? You'd need a super strong engine to even get it to rev high enough to reach 44. But until I see proof, I'm not believing, sorry.