As you can see I had to make some pretty serious frame modifications to be able fit the 75cc engine in it. I had to cut the frame at the pedals and make it longer, I used the front fork off of another bike to make the frame ling enough to handle the engine the fork also made a extension because it offered a great spot to mount the motor to. I beefed up the top frame rail with a heavier stronger steel tube, and the back frame had to be reworked to make clearance for the motor.
You will also notice that the engine also sits to one side. i did this to balance the bike side to side so it doesn't pull to one side or the other. The problem was that the flywheel was so heavy that I had to move the engine over so much in order to balance it that it sticks out the side. This lead to another problem when lining up the drive system.
Because the engine was so far to one side there was no way of running a chain to the rear sprocket. What I did to solve this was add a gear casing thing to the side of the frame it has an axle that leads to another gear that lines up with the rear sprocket. this setup is a little awkward hanging out the side but it was the only way around the problem.
