Looking for a CV Clutch expert

[garydee]

Since I've gotten my cart together, me and the kids are having a blast cruising around the neighborhood. So it will be in the family a bit longer, time for a couple more issues to be rectified with it.

The cart - 89 Cushman UTV Max - 14HP Vanguard Twin, 480 Hours, comet clutch (?);

When I got it, the drive CV clutch was seized up. Once I broke it loose and inspected it, it was really ragged out. The weights were loose, the arm bushing holes were wallowed out and it had two broken springs.

After web searching, I came across an "new" old set of arms, weights, springs and bushings.

Here's the issue; Only weights I could find are a lot smaller/lighter than the monsters that were on there. Also, to match the lighter weights I had to use lighter springs (I think it came with purple springs).

Result; disengages fine, but seems really "laggy" on take off. Hit the gas, jumps a bit, than very slowly gains speed, than vroom - off it goes. On slow take off, the engine really has to rev before the clutch starts kicking in. Top speed with 25inch tire is about 14mph. For a 14HP engine, it just seems doggie.

The attached picture is exactly what my clutch should look like (with correct weights, from what I can tell). I have included this for identification.

Now here's my delima - should I keep looking for more weights and springs to tune this "out of date" drive, or just replace the whole thing with some type of newer style. What would be a good replacement?

Also, how much difference would it make in top-end speed going to a larger drive?

Any insights would be great - please let me know - Garydee

[scottyb]

What size is the shaft on the Cushman? I dunno about trying to find comet parts right now,..... you know they went belly up last fall?

Lighter weights should engage sooner so maybe you are having driven clutch issues also not disengaging all the way?

[roady89]

Originally Posted by scottyb

What size is the shaft on the Cushman? I dunno about trying to find comet parts right now,..... you know they went belly up last fall?

Lighter weights should engage sooner so maybe you are having driven clutch issues also not disengaging all the way?

Not trying to correct anyone but lghter weights bring the engagement point up (revs higher before engagement). Heavier weights come in sooner. Springs with less tension will shift out quicker, more tension the shiftout takes longer....then cams etc will do different tunes.

There are comet parts available....they are just harder to find. I think you'd be money ahead to just replace the old girl with a CVTech or comet clone. I hear good things about the CVTechs.
Couple good threads to read on clutches.
http://www.buggiesgonewild.com/big-b...h-options.html
http://www.buggiesgonewild.com/big-b...ock-carts.html

If you really want to repair the clutch then have a look here. That looks like a comet 780/salsbury clutch. The manual on this page will have lots of good info. http://www.buggiesgonewild.com/big-b...80-1190-a.html

[garydee]

Thanks for the info gents. I have spent the last couple of nights searching the web for CVT information. Boy, since Comet went out, looks like there is a pretty big void for options on CVT's out there. CVTech looked interesting, I just wish they had more info.

A couple of interesting notes I derived from your suggestions, watching my carts CVT operate while going down the road (with my son driving) and watching videos of properly working CVT's.

At WOT, I could see that the belt never "sank-down" far into the "driven" pulley (you got it scottyb). Looking at the "driver", it never completely engage (belt would ride toward the top, but not high enough). My original thought was that the lighter weights I replaced in the "driver" just did not have enough weight for the RPM.... Humm.. RPM. We were just not getting enough revs!

I popped off the Morse-Teleflex throttle cable and checked the gas pedal pull. Sure enough, I was only getting about half throttle. After a couple of adjustments we were off again. The engine revved higher than I have ever heard since I got it running. Out of the hole it was still a bit soggy, but after about 6 or 8 MPR she took of. It was like a new cart! We clocked it at about 19.5 on the GPS - now that's a difference!

The other issue I have found out about CVT's is the belt slack. From what I read, it needs to be about 1.25 to 1.50 inches - mine looks to be about 2 to 2.25. I hoping to tighten that up over the week-end and see if that make a difference on top end.

Bottom line, I guess this old setup still has some life left in it. I would still like to find some heaver weights in the "driver" to better use the engines torque for the initial "go" (engaging it quicker). You guy's know any sources for weights and springs?

roady89 - I agree it looks like a Comet / Salisbury 780. There was a nice one on eBay for $80, but it looked like the shaft hole was too small (1 inch). I'm told by Briggs mine has a 1.25.

Thanks guys!

[garydee]

I thought that I would add a note in here about my CVT Driven. I finely got a new replacement from Tom at Carts Plus. Because of space limitations, I went with the CPP-06 Big Block setup. Wow, what a difference! I gained about 3-4 MPH and the torque is fantastic! I can tell that now I am utilizing the power of the engine. I just wish I would have done it sooner and saved the $$ trying to keep the old Comet still working.

I will have to get a "Driven" clutch down the road if I cant fine a replacment rear axle. At least I know who to go to!

Thanks Tom and the Carts Plus team.

GaryDee