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Old 04-09-2009, 09:58 AM
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Pablo Pablo is offline
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Join Date: Dec 2007
Location: Duvall, WA PNW
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Default Re: jack shaft on a cruiser

Originally Posted by toytime View Post
No wait, I am correct to say that the crank is always spinning if you are running the motor.
The correct way to think about it: The crank arms are firmly attached to the spindle. This is a fact. We must agree on this. But yet with the Shifter Kit, the pedals don't turn under engine power.

The engine rotation under engine power with the Shifter Kit is transferred to the front chainring via two chains and a solid shaft. This is a fact. We must agree on this.

This front chainring is also solidly connected to another chainring which via a chain drives the rear gears and wheel.

So we have a set of two front chainrings which are bolted together - but these are attached to a freewheel, which rotates freely ON the right crank with engine power. And when you pedal and only when you pedal the freewheel engages and drives the spindle and chain and rear wheel.
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