How fast is your mini bike

My longest straight away is only around 150 yards before I have to hit the brakes. With a mildly built 196 on a Baja frame and my 230 lbs, I can hit 35mph (gps). and it is still pulling. I’d guess it’d do 40-45 mph with some more runway and the current gearing. Maybe 50 with a sprocket change, as I have it geared low for hills.

I hear that if you change your speedo app to kph, you‘ll go faster!
What is your current gearing .sprockets?