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Old 02-16-2011, 07:45 AM
Creative Engineering Creative Engineering is offline
Join Date: Sep 2008
Location: Clearwater, FL
Posts: 1,668
Default Re: Centrifugal vs. Clutch Engines

I've never had one of these...but it makes sense that a sprag is used.

For those who don't know what a sprag is: It's a one-way bearing...the same concept as the freewheel sprocket. It spins freely one-way, and locks when rotated in the opposite direction.

I assume that the sprag/bearing is between the clutch bell and the crankshaft. The mounting hub for the shoes would be directly connected to the crankshaft.

When bump starting, the clutch bell locks with the crank to turn the engine over. Once the engine is started the crank spins freely inside the bell, until the shoes expand and drive the bell.

What I don't understand is:

How you could simply remove the sprag/bearing without replacing it with something? Standard bearing, bronze bushing, something.

Is the bell supported by 2 bearings?

I would like to see pic of this.


Last edited by Creative Engineering; 02-16-2011 at 07:48 AM.
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