Step 3: The Drive shaft/roller
this is the piece that transfers the power from the engine to the wheel. I had lots of ideas about this, including using bike pegs, making my own, scooter wheels etc ( I saw someone use a socket and it slipped against the wheel and didn't work at all if he went through a puddle)
I had sum bike pegs I was going to use but they had imperial threads and my clutch used a metric thread and I didn't want to make an adapter so I decided to make my own.
I needed a lathe to make my own but so dad knew a bloke with one and he made it for me. it fit nicely into my clutch housing and threaded right into it.
the size of the shaft/roller matters as it affects the gearing of you bike. you will need to work out revs of your motor, size of your back wheel, how fast you want to go etc, to decide on the size of the roller.