Two speed centrifugal clutch

[Jhoppe]

I've been reading a lot of these old two speed minibikes and I am struck curious. They seem supercomplicated, but my uncle swears the one he had as a kid was stupid fast. Why arent these popular? Would it be worth replacing my torque converter? Maybe a neat project cart in the future? Thoughts?

 

[anickode]

Torque converter gives you a broader "gear" range. These clutches were more popular when you couldn't get a tav2 on eBay for 50 bucks.

They aren't popular because the setup uses an "inside out" clutch, where the sprocket is connected to the guts, and the Bell is connected to the shaft. The sprag bearing would be the toughest bit to source, especially if you don't have the resources to do any machine work. The parts are quite expensive, and by the time you've spent all the money on the parts, you probably could have bought an genuine comet brand torque converter.

They are neat though, I'll give you that. I rode a minibike with one, and it's much more exciting than a torque converter one second gear actually grabs. But I wouldn't say it's really any faster.

 

[Jhoppe]

I was just wondering. I didn't even know you could do it until I saw that particular episode of cars and cameras. I have never seen the set up on a go-kart either so I was wondering why that is. I have access to a machinist and a mill/lathe. So I can get most of the parts made pretty cheap. I am happy with the torque converter I have so maybe I can do another project with that setup later. I have seen a few setups online that just use two jack shafts and two regular clutches, but they look super complicated

 

[Jhoppe]

Running the rough numbers it looks like about $132 for just parts. Not including chain or shipping. I might have some of the parts around, but that seems impractical vs a torque converter

 

[mckutzy]

The 2 clutch method is the easiest, as they are just regular clutches that have adjustable spring sets... However in this setup there is a sprag bearing sprocket(one-way bearing) on the jackshaft from the first clutch.... This allows to override the first ratio and allow the second clutch to be powered and not fight against the first...

If given enough space and thought about it...One could time the clutches with the engagement springs at the right ratio's, that they could have more than 2 clutches in a string. A progressive cent clutch multi speed setup if you will.....
BUt the amount of setup and space, kinda out weighs the pain for going onto a TC and set that up....