Welcome to my world-I say my world because this is a very personal hobby. Ah It is normal for things to NOT fit. Get used to that. Your patience, knowledge, and mechanical skill is critical to bring you and your bike to a safe and happy place together. I don't know your weight but heavy guys still ride and enjoy these bikes which are designed to be low power and only to assist secondary to your legs. I weigh 150lbs last I checked. My steel frame Huffy with worksman wheels is 60 lbs. The Engine manufacturer claims these motors to be at 2.75 horsepower. That's not much. It's basically a 1 speed motorcycle. so the power band is very narrow and tapers at both ends before and after peak (2.75 HP) power. I think you are experiencing the limitations of the motor design. Nothing is wrong-It gets better after break-in. Your immediate challenge is to take care and keep it whole and running all the while keeping yourself safe... You are now involved in a hobby many others have taken on. One hour reading posts on this forum equates to an immeasurable amount of time thru experience on your own. Be patient you are now subject to some painful heartbreak and overwhelming joy. Accept both and good luck!