Teenage Dream

Making real progress on my motorized bicycle, the Teenage Dream. After riding it happily for a while I became weary of the single speed setup the kit comes with, knowing that there were kits to run the motor through the bikes existing gearing system I decided to make my own setup.
Power comes from the motor to a jackshaft which brings it from the left side to the right (where the transmission is), from there it travels via pulley down do another axle where the chain finally sends power to the back wheel. The pedals have been eliminated, I plan to bump start it until a pull-starter can be worked out.
Fabrication of the lower pulley had already been documented, but making the sprockets and bearing brackets were quite challenging.
Also visible in this photo are the fire extinguisher fuel tank and the ported exhaust pipe, which will soon be modified with a tuned resonance chamber for more power.
It all still looks like a bit of a mess but it will come together into a fun little scoot I believe.

Pulley Penicillin

To finish the pulley the last thing it needed was a hub suitable for the 3/4" axle, thankfully I found inexpensive 3/4" collars at Ace Hardware. After centering the collar to the balance point I found previously, all it needed was to be welded.

Not my best weld ever, but it's strong, on center, balanced, and these welds are on the backside so not visible. Overall win.

More work on the motorized bicycle coming soon.

Pulley Fever II

Previously on Conjectural Technologies...
I cut a single two-groove pulley in half, making two pulleys.

And now the continuation...
Because this was a harmonic balancer the hub was pressed in with a rubber ring between it and the pulley, knocking it out with a sledge was easy.

Then I traced the core's outside diameter onto steel.

Which I cut out and welded into the pulley.

Now to find the center of my new pulley, I clamped a nail in the vise (checking that it was 90° straight up), and placed the pulley over it, adjusting it by hand at first and then tapping it with a small piece of steel bar until it balanced on the nail.

I eyeballed the pulley as being level, as close as I could get it, then hit it with a hammer so the nail underneath would leave a mark, like a center punch.

This is definitely a primitive way to do this, using appropriate tools it could be achieved with less work and greater accuracy, but I'm working with what I've got.
Next up use to put a 3/4" hub in the center for the axle.

Pulley fever

I need a large pulley for the transmission on the motorized bike, but they're hard to find, and why buy what you could build?
I took the crank pulley from one of my spare Nissan Z-car motors.

But it's very heavy cast steel and has two grooves when I only need one. So I used a DeWalt angle grinder with a cut-off wheel slipped into the small gap between the pulleys to separate them.

It took a while, and because the cut was so deep and narrow the wheel had almost no room to move or tweak.

Now I have two pulley rings, next I have to make one of them mate to the axle of the bike.