Driven CVT Clutch to Gearbox Mating

[SCBaja]

I'm working on a small buggy in the SAE Mini Baja Design Competition, I know there are a few Baja veterans on this board, and a great deal knowledge outside SAE Baja as well. *Our team is considering the use of a high/low/reverse gearbox from an ATV. *The first step in the drivetrain will be a CVT configuration; a drive clutch on the engine output paired with a driven clutch on the input of the gearbox; The problem is, our driven clutch is keyed, and the input shaft for the gearbox is splined. *I was wondering if anyone has any experience with dealing with this problem, and any advice on how to adapt the driven clutch to mate with the gearbox without destroying it.

Thanks,
Steve

[Philabuster]

Simplest solution (read--cheapest) would be to make the original secondary that came with the gearbox work for your application. *Sounds like this is a Polaris gearbox.

[SCBaja]

Yeah, buying a polaris secondary is a possibility; we were also thinking ofpulling out the input shaft and trying to turn the splines down smooth, make an adapter, and weld it up; not sure if we could do this without damaging the saft. *The only non-invasing thing I can think of would be having our secondary running on its own shaft, supported by two bearings, and some sort of coupling from that shaft to the splined input of the gearbox. *I'll probably get with our machine shop guy and get his opinion too. *I think this is goign to be the biggest hurdle with our design.

[hero_saku39]

driven clutch off of the smaller 4 strokes from early 00's is only about $300.00

[Philabuster]

Originally Posted by SCBaja\";p=\&quot

Yeah, buying a polaris secondary is a possibility;

Used Polaris secondary clutches go for under $50 on Ebay all the time. *I bought a new one for under $100 a few months back. *You can adjust spring settings fairly easily or get different helixs and the best part--IT WILL BOLT UP.

Don't ruin the input shaft and delay your build when you could easily solve your CVT issue with the correct parts.

[Bugpac]

I agree, pm renegade spec, he likely has a polaris driven, dunno if its an atv driven or if a snow machine driven is the same or not tho....

[minibajaman]

Originally Posted by SCBaja\";p=\&quot

Yeah, buying a polaris secondary is a possibility; we were also thinking of pulling out the input shaft and trying to turn the splines down smooth, make an adapter, and weld it up; not sure if we could do this without damaging the shaft. The only non-invasing thing I can think of would be having our secondary running on its own shaft, supported by two bearings, and some sort of coupling from that shaft to the splined input of the gearbox. I'll probably get with our machine shop guy and get his opinion too. *I think this is going to be the biggest hurdle with our design.

If you are using a Polaris gearbox then you might as well use the Polaris CVT as well. *It would not be worth the effort to modify the shaft as you are suggesting. *The input shafts are I believe hardened somewhat which would make machining difficult and welding not a good idea. *And you can get the Polaris parts thru the sponsorship way cheaper than anything else. *Don't do a jackshaft just to run a different clutch, too many extra parts to break.

I'm assuming that you are looking to use a Comet or CVTech CVT instead. *The team I was on used Comet the last couple years, they work pretty well, but are less tuneable than the Polaris or CVTech. *Many years ago the team actually used a Comet primary with a Polaris secondary, and it mostly worked ok but the Polaris would always break the plastic buttons inside. *I don't think many teams running matched sets have this problem, and the Polaris clutches may have been improved since then. *I would say if you are set on using the Polaris gearbox then go with a Polaris CVT set as well.

[desertkart340]

We are working on a desert kart with a arctic cat 340 f/c. I'm interested in what polaris gearbox you used. How did you mate the half shafts to the gearbox??

Help needed

Charlie

[umbaja2009]

In order to solve this problem on our car, we built our own sedondary. But I think you would have the best luck building your own input shaft to the Polaris gearbox if you want to still use your secondary.

[nutz4sand]

Originally Posted by SCBaja

I'm working on a small buggy in the SAE Mini Baja Design Competition, I know there are a few Baja veterans on this board, and a great deal knowledge outside SAE Baja as well. *Our team is considering the use of a high/low/reverse gearbox from an ATV. *The first step in the drivetrain will be a CVT configuration; a drive clutch on the engine output paired with a driven clutch on the input of the gearbox; The problem is, our driven clutch is keyed, and the input shaft for the gearbox is splined. *I was wondering if anyone has any experience with dealing with this problem, and any advice on how to adapt the driven clutch to mate with the gearbox without destroying it.

Thanks,
Steve

Can you post a pic of your input shaft and the driven clutch you wish to use? More importantly measure the diameters of the tranny shaft and the inside of the secondary and post them on here. Being most Bajas are running 10 horsepower or close this below should handle the power pretty effectively.

IF you have enough diameter you may be able to take a clutch that fit the tranny in the atv it came out of and simply machine down around the splines till it fits inside the drivens diameter of your driven then simply cut a keyway to match keyway of the clutch. I think I said that clear enough you should understand it. If not I can get more into detail.

If you have the diameter available this would be easy to do. Getting a old or worn out clutch off the atv for the splines should be cheap.

Post the pic and measurements anyways. It might help someone help you.