Bryce, I read his last post diffrently. It sounds to me that he only had the 50cc for thirty miles. He didn't break anything on it! Don't worry, I am sure we have all misread somthing at that hour of the night[img]i/expressions/face-icon-small-wink.gif[/img]

 

Bryce,
Wonder why it was the Polaris quads that had transmission problems with such low low miles? [img]i/expressions/face-icon-small-wink.gif[/img] Seems they don't hold up all that well. Could that be? Maybe I made an assumption.

Actually, if you consider there are four of us in our family, and that we ride during the week and on every weekend, with four machines going at once, I'm going to estimate about 1600 miles per month that we put on them. Not 1600 miles each, but split over 4 of them. So even if we only keep one particular ATV for two years its not exactly like these are low mileage units. One of the Grizzlys we owned had 3500 miles on it, a DS650 had 5000 miles on it, the Grizzly 700 has 400 miles on it since we bought it on labor day weekend started. Its best not to make assumptions.

 

Same old "if your Polaris broke it's your fault". Don't even waste your time with this guy.

 

Propnut, as usual, your goal is to turn a potentially useful thread into a useless squabble between brands. Lets see if we can get it out of the gutter eh??

There are two classes of CVT type transmissions in ATVs. The first class is CVTs that use the belt as the clutch. This type of CVT system is used by Kawasaki, Suzuki, Polaris and Bombardier.

The second class of CVT systems are those that use a separate centrifugal clutch in combination with a pretensioned CVT belt. This type of CVT system is used by Arctic Cat and Yamaha.

I think the clutches advantages and disadvantages can be summarized as follows:

The advantages of the belt clutch systems are:

1) Simplicity, this system uses the belt as both the clutch and the transmission
2) High performance: these clutches provide a wide range of custom tuning. Specifically, engagement speed can be closely tied to engine HP to provide very high launch rates. Similar to “clutch feathering” on manual transmission quads.

The disadvantages of the belt clutch system are:

1) If the rider makes a habit of riding the ATV in such a way that the belt slips, he can burn the belt up.
2) Since these systems are so easy to change the tuning, often times custom tuning results in reducing the reliability of these CVT systems.

The advantages of the belt system with separate centrifugal clutch are:

1) Idiot proof: It is not easy to burn this system up because the CVT is not used as a clutch. Furthermore, the centrifugal clutch engages over a relatively small rpm range to limit wear to the centrifugal clutch.

The disadvantages of the belt system with separate centrifugal clutch are:

1) More complicated: The CVT system is more complicated because it includes a separate automatic clutch with its own wear surfaces. It also requires additional bearings/seals built into the CVT drive clutch that allow the output of the clutch to free wheel on the crankshaft.
2) Little performance tuning: Very little can be changed in this CVT system to increase its performance. The centrifugal clutch is pretty much on or off, there is no capability to provide a “Clutch feathering” type launch. This system depends on engine torque to launch the quad.

 

Again you turn a thread into a Polaris advertisement for dummies. I don't see where I am endorsing a brand or approach to belt drives, just pointing out your bias based off of misplaced American (well, sort of) company protectionism. Just listen to the people with experience here and quiet about your inexperienced theories. Drop the condescending criticism because of their bad experience with your favorite brand. If I was buying a belt drive off of experienced owners opinions, I would totally disregard your rhetoric. The point of my post was to identify your post as such, no offense.

I will say that you are wrong about the Polaris (for example), the primary is the "clutch", not the belt. The way the primary is allowed to "let go" of the belt handles engagement and disengagement. Boy are you off on that flawed interpretation. Engagement in a non-drag racing machine is less than 1% of where an ATV spends it's time and seeing there is such low gearing and virtually no wheel slip (like a sled track on different conditions that require different engagement characteristics) there is little need to alter it's engagement. There are times that would benefit, such as going to a larger heavier mud tire in competition, but that can be taken care of in ways other than a stiffer primary, notched weights, or whatever other trick used on a sled type CVT.

Because ATVs are not lined up for organized drag racing as commonly or competively as sleds, not many owners need to tune the engagement speed. However, stiffer springs for centrifugal clutches are available for some models that increase the engagement RPM, so you are wrong about that too. You can still tune upshift, backshift, and RPM by using the same techniques as a sled (helix, springs, weights), but then again you personally don't really mess with that stuff on your machines so your response is not based off of experience. I would hope this thread would continue to be populated by owners that have had a few different types of ATV belt drives and post from a lot of experience.

 

I take it being an American is bad in your eyes????
I don't see where I mixed up the primary and the belt. However, what I was refering to is that the belt and primary form the clutch on a Polaris (for example). The primary is simply a couple of sheaves, springs and weights. It performs the function of a clutch when you add a belt. On the other hand, the centrifugal clutch performs the function of the clutch on the Yamaha and Arctic Cat: not the belt.
Clutch feathering is used to launch a manual transmission quad as quick as possible. Its intent is to prevent tire slip. Ask anyone familiar with manual transmissions. Not sure about your point about low gearing since the intent of the CVT is to pick an optimal gear ratio. As far as 1%.. so what??
It is well known in both the ATV and sled forums that tuning of the clutch and specifically changing the engagement speeds and shift up rate from stock settings invariably gets you out of the hole quicker. Stock clutching on many ATVs is often too tame for some riders. I personally prefer the stock settings on my quads.
You need to go to Silver Lake on any weekend during the summer. You will find hundreds of quads watching and running against each other. Here you wil see everything imaginable from hopped up banshees to dune buggies. It may not be organized by a drag racing body.. but it is huge and there is a lot of money dumped into these machines.
The centrifugal clutch has a very limited RPM range of slippage. For good reason, it has virtually no ability to get rid of the heat. Look at the design. The CVTs have cooling fins hung all over them. The centrifugal clutch has no such cooling fins. You will burn up the centrifugal clutch in no time if it slips. The slippage is what allows you to come out of the hole so quickly. The CVT will always do better than a centrifugal clutch.
If you read my post I specifically refered to engagement speeds, because that is the key characteristic that that is often very low on CVT driven quads. Sleds typically don't have this problem. But I doubt that you will find hardly any performance parts for either the Yamaha or Arctic Cat clutches.
I am the only one that every lays a wrench on my toys. But then again how could you possibly know that. You don't know me.

Always nice to chat propnut

 

My '02 Grizzly (which I've owned and ridden since July of '01) is still on the original belt, in fact the belt cover has never been removed. I have about 3800 miles on this machine now, it works hard (dragging logs out of the woods every year, some of which are so heavy that I need a running start with slack in the chain to get them moving) and it has played hard (those that have ridden with me know how and where I ride). I've had to replace my hitch with a home-made design that was stronger to keep it from breaking with the abuse that I put it through and I've had some front-end components replaced due to normal wear. Nearly all of my trail riding has been in high range as well, the exception being when going through boulder fields or descending really steep, technical hills. For those situations I use low range and 4WD.

My Brute Force 750 on the other hand is on its 3rd belt now and it only has about 2500 miles on it, and I've owned it since around August of 2004. It is strictly used as a play machine and is the one I normally use these days for trail riding when I want to use a utility quad. It has been spared log dragging work as I use the Grizzly exclusively for that.

Anyway the point I'm trying to make here is that my Grizzly sees more abuse (although there is less torque involved as well) but the belt drive system is holding up substantially better than on my Brute.

I don't have first hand experience with the others, so I'll refrain from commenting on those...

 

you said it, not me. backtracker.
wet clutches like the Grizz wouldn't work well with fins smarty, would they? They'd probably foam the oil and get too hot, nevermind power loss.

I love American, just don't like your Rovian tactics. You know a competitive brand that's all American I can buy? Truth is that this is more BS from BGTX the defender. You are just like Dick C. Too old and/or too stubborn to change or admit you're wrong.

Both styles of CVT can be tuned for better performance (see Dalton for one), from idle to shift out, regardless of your disinformation. Engagement speed on a centrifugal clutch is low enough that you probably won't notice, but there is enough slip to make it smooth. Because of the gearing, engagement with the belt is practically insignificant on an ATV, it's the upshift/backshift that matters. You spin it to make it sound like a centrifugal clutch on a belt drive is a disadvantage. (maybe it's an excuse for the old fashioned sled type) Try driving one first. Better than burning out a "Lifetime Warranty" belt that you have to pay for anyway.

So, where's the big utility ATV drag race like Haydays? I'll be sure to bring a pillow zzzzzz. 25 second 1/4 mile runs!!! wooo hooo

The belt is not a clutch, no matter how you "spin" it. I've said what I have to say, so type what you must and say it over and over to convince yourself you are right. I'm taking the high road, bye.

 

I stand corrected about performance parts for the Yamaha clutch system. EPI makes a clutch performance kits that "raise the clutch engagement speed" which is clearly the performance bottleneck in any CVT powered quad. My 2 cycle quad has an engagement speed of 1500 rpms. My two cycle sleds have clutch engagement speeds of 3500 rpms. A reclutched quad gives a performance boost that suprises most people. The only place I have felt the need for higher engagement speeds is in the dunes where performance is critically important.

As far as cooling the clutch, it seems to me that the rotating fins on a CVT primary will dissipate much more heat than the air going through the oil cooler for the engine oil. Centrifugal clutches are design to slip as little as possible. It won't last long if it does. It has more in common with a manual clutch than a CVT clutch.

It is not my intent to bash any CVT design, only to point out what I see as the fundamental differences. It is hard to argue which design is simpler. We can argue all day about which design is more reliable. From a performance standpoint, it seems to me that the the limitation of slippage of the centrifugal clutch puts it at a disadvantage.

propnut, you can argue all you want about the sematics of what is a clutch. If thats all you got.. you might as well leave.
Bryce

 

I have a 650V2, with Kawis tranny, and took the belt cover off to check the belt at 1000 miles. The belt is still new. No joke. It doesnt matter what you have, it all about how you listen to fellow riders, and how you treat it. I drive mine in low ALL the time, as i was reccomended. And it paid off. I can jump, pull wheelies, beat the crap out of it, and havnt had one sign of wear on my belt. Just take care of your machine, and it will last a long time[img]i/expressions/face-icon-small-wink.gif[/img]