Where to put sprag spring on centrifugal clutch


New Member
Jun 15, 2018
I finally managed to buy a centrifugal clutch kit for my 49cc Chinese 2-stroke conversion engine. It's been great fun thus far, but I could really use that automatic clutch. The kit seems quite complete, but I think the wire spring that somehow holds the sprags of the one-way clutch in position wasn't in the correct place.

So I spread out the parts on my unmentionable clock-repairing carpet and took a picture, three copies of which I have inadvertently uploaded here. (A) is the spring in question, and what it's supposed to do according to another post in these annals is hold the sprags, which are the five tiny cylinders surrounding the hole in the silvery cup to the far right. I think the spring is supposed to be looped onto itself to form a springy ring, but it didn't come that way and I cannot figure out how it might fit onto, around, or inside the circle of sprags. If anyone knows how this thing is supposed to go together, I would be eternally grateful and will speak on your behalf come the Day of Judgement. If it's the wrong length spring I can make another from piano wire.

I also wonder about the big black bolt, (B), which seems to be some sort of an extraction or installation tool. It threads nicely into (D), which is the hub of the silvery cup and which engages the sprags therein. There is a small hole in the side of this hub, and I assume that its purpose is to convey lubrication from somewhere onto the sprags and other bearing surfaces. Some wisdom here would also be appreciated.

Bolt (C) would seem to thread into the engine's crankshaft such that it holds the black hub (D) firmly in place so it can act as a crankshaft extension. Is this correct, and is bolt (C) the one in which I should mount a grease fitting so that a shot from the grease gun will lubricate the clutch? I saw a fragmentary discussion of this idea in a somewhat-obscure YouTube video.

The bike is an ancient Schwinn with a one-piece crank (not the original crank, which abruptly broke in two in normal use, thus depositing me in the middle of Misssissippi Rte 82 near Lumberton in 1993.) This won't clear the case enclosing the new clutch, so I'll offset the crank a bit by either cutting and welding or just heating and bending it.

Any further help on this project and or suggestions for pertinent articles or videos will be welcomed by both me and my patient spouse, who is weary of hearing about my motorbike clutch.

Mark Kinsler
Lancaster, Ohio USA
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