[Kartbuilding] centrifugal clutches

[Stephen Burke]

Hi Tim,

The easiest way would be to get the transaxle/gearbox from a 
ride-on/tractor lawnmower, however as you said below, these would have a 
very low gear ratio and you might have to gear up.
To be honest, no matter what gearbox/transaxle you get, it will be very 
in-efficient. There will have to be two drive connections:

engine -( chain )-> transaxle -( chain )-> rear axle

I tried the above before:
http://www.kartbuilding.net/gallery/v/Kart_Clearance_and_Memories/DSC00978.JPG.html
and again had to gear up quite substantially. Although the setup worked, 
it weighed a lot. It would be possible to eliminate one chain from the 
above setup by using a coupling, however this would be expensive.

Searching for a gearbox/transaxle on northerntool.com revealed little 
suitable options for a kart.

To conclude, I dont know of a special gearbox for a gokart which will take 
a vertical input. If you obtained one from a tractor/ride-on lawnmower and 
adapted it to suit, while it would work, it would be innefficient and 
heavy.
I suggest you look towards small motorbike engines altogether. This is 
what I have done, and it is much easier and more efficient. See:
http://www.kartbuilding.net/gallery/v/Off-Road_Kart/DSC04640.JPG.html
I paid 100 euros for a 100cc motorbike engine at a motorbike repair shop. 
It has 4 gears and a manual clutch.

The v-belt, centrifical clutch and transaxles are if you want to bodge / 
engineer some setup with minimal cost.

Best of Luck,
-steve

On Fri, 1 Feb 2008, Tim Valis wrote:
> Actually, I've been considering the possibility of using a transaxle, but
> I'm not sure what kind to use for a go-kart.  Most lawnmower transaxles have
> poor gear ratios to be used for go-karts, and they often wouldn't be able to
> take thekind of beating a go-kart would put out.  Are there transaxles
> designed for go-karts?  If not, are there other options available?  I would
> like to have the ability to shift gears (I plan on racing against a friend
> of mine who already has a kart!) and so a multiple gear transaxle is rather
> appealing to me.
>
> Thank you for all of the information about centrifugal clutches and
> V-belts!  If I can't make a transaxle work, then I will probably just use a
> V-belt and have as much fun as I can!
>
> Thanks again!
>
> -Tim