Help find a clutch for a rotax 640

[Dan93]

I need help finding a clutch for a rotax 640 it has a tapers sahft Whit treads at the end I'll post some pics thanks

 

[landuse]

You are not going to get one that will fit a tapered shaft. Period. All you could do is swap out the crank for a straight shaft and then look for a clutch. Which is going to be difficult because of the size of the engine. I think maybe the comet Duster? should work. The comet 40 series is rated to 18HP as well I think. I am not too sure what 640 relates to in HP

But unless you get a straight shaft on that thing, you aren't going to find anything

 

[Randy H]

https://www.mfgsupply.com/206098a.html

Possibly correct. Can't really tell from your pics.
Different years had different clutch retention methods.

This pdf has info pertaining to using the 94c on a Rotax.
https://www.denniskirk.com/dk/pdf/instructions/38/dk3836.pdf

 

[Kaptain Krunch]

You will be best off getting the clutches from the snowmobile that engine originally came on.

 

[Dan93]

I know the old clutch was a square shaft but I don't know if the shaft on the engine is 3/4 or 7/8 on the tread side i got the engine alone a never saw the snowmobile it came of off my guess it was a tnt or Alpine I'll upload some picsof the shaft Whit measurement maybe it will help

 

[Dan93]

Here is some better pics of the shaft

 

[950speed]

You could probably get/make/get made an adapter to get rid of the taper

 

[Joe-405]

Or could pull the crankshaft out and have a machine shop make it normal ? If there is enough room to do so on the thin side of it.

 

[anickode]

You guys have to think beyond the comet 30/40 series.

The VAST MAJORITY of torque converter/CVT clutches have tapered shafts. ATVs, snowmobiles, UTVs, golf carts, etc.

Granted, most of them also have splined shafts on the driven pulley, but a lot of them can be mixed and matched with some research. You could also have the splines bored out of the driven and a keyway broached.

---------- Post added at 10:49 AM ---------- Previous post was at 10:47 AM ----------

Or could pull the crankshaft out and have a machine shop make it normal ? If there is enough room to do so on the thin side of it.

Yep. You could get your crank turned down to 1" with a keyway.

The problem is most go kart torque converters will self destruct long before that engine runs out of revs, and a 40 series wouldn't handle the power anyway. You'd be better off finding a snowmobile clutch that will fit, and either using the snowmobile gearbox, or modifying the driven to work with keyed shafts.