DIY Electric Bicycle, Entry #6: How It Goes Together (still continued)

After mulling the requirements and several ideas around in my head, I figured out a way that I could make it work.
The current plan is to build a rack to mount on the back of the bike, to which the motor will be attached. I decided to make the rear wheel pulley-driven, rather than chain-driven as I had originally thought. I will be using the V-pulleys from an old Volkswagen Beetle engine, with the smaller pulley on the motor shaft, and the larger welded directly to the rear wheel. Just in case you don't know what a VW engine looks like, here's a photo showing the pulleys that I will be using:
View attachment 247
You can see in the photo the two pulleys right on the front of the engine. Those are the pulleys I plan to use. If this pulley arrangement does not produce enough torque, I will simply find a smaller pulley for the motor. Easy enough.
I still had a problem with moving pedals, though. If I had the pulley connected directly to the wheel with the sprockets on it, they would still spin. Before deciding what to do, I decided to test my motor, to see which way the shaft turned when the case was connected to ground and the power wire connected to positive. The motor shaft turned the wrong way for what I was planning anyway. Then I realized that if I welded the large pulley to the opposite side of the rear wheel from the sprocket stack, the motor would be turning the right way AND it would allow the "ratchet" mechanism to work. When the motor is spinning, the ratchet works and the pedals do not move. Perfect!
I had hoped to give a good sketch rendering of the entire layout, but I'm afraid I'm really bad at drawing. All I can give is this MS Paint silhouette drawing of my plan:
View attachment 246
I'll post it later with all the labels and everything. I hope this is sufficient for now
My next entry will describe the power and control system for the motorized bike.

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