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The reason all CVT Belts fail. Read this!!

66K views 39 replies 18 participants last post by  patov6  
#1 · (Edited)
All belts no matter who makes them fail if the conditions are not correct and the culprit is heat.

All belts other than the cords used in them are rubber, it has no tensile strength and has no bearing on how strong it is, the cords in it is where the strengh is. Rubber melts no matter what you make it from. Does anyone have any tires they can spin on pavement and not wear them out? No, well why are we asking rubber belts to do this?

So what makes all belts fail? Heat from one of the following conditons.

Keep in mind a totally stock machine with stock tires and riden in a none severe manor the belt will last the longest. Anything outside that the life of it starts cutting down but it can be avoided with proper precautions.

Bigger and heavier than stock tires puts excess load on the engine and clutch, to properly handle this a clutch kit is in order to put the clutching back in proper calibration. Without it the belt will shift out too soon and put a excess load on it and that creates heat.

Clutching, basically for the reason above but also because you ride in the dunes with heavy sand or you and your passenger are heavy people, or you have added a couple hundred pounds of accessories to your machine. You need to reclutch it and the belt will get hotter than normal if you don't.

The use of low range, most people use high range when they should be using low range. Belt temp testing proves there is a huge difference in belt temps when using low range versus high range and less slippage. One in low range you are letting the belt ride higher on the primary and it has more grip there and two the engine is turning more rpm which makes air flow better through the clutch fan and cover. Low is cooler and high when traveling less than 25 mph for extended periods is high heat.

Snorkels, most snorkels restrict air flow but some people get away with it since they just ease around and don't create a bunch of heat to begin with. But the people who go buck wild and have small snorkels will create excess heat and the belt fails or slips.

Clutch alignment, the 800's are known to be out of alignment and that in itself causes heat.

Binding primaries or secondaries, any time either get dirty they can bind and not let close up like they should and have you hitting the rev limiter at odd ball times and that creates heat.

Wrong clutch kit or wrong calibration. If you have a bad kit or yours set up wrong it creates heat.

Riding style, extreme riding on and off the throttle like racing, riding for hours non stop, riding too slow with little air flow, mud riding, wall climbing etc all create heat. Me personally, I cross country race and I have never ever had a belt failure. I actually ran two seasons on the same belt and won two championships on the same belt, mentioned axles never broke one. Why? Foot control for the most part and having the right set up of clutching, tires etc.

As you can see heat is the issue and it can be prevented by you.

There are some substandard belts and there are some good ones like the Gates C12 Carbon fiber we sell. Before you do anything you have to assume you have a good belt to start off. If you are blowing a OEM belt in a couple hundred miles then simply swapping to this belt will not fix your issue, you have other issues going on that need to be addressed.

What makes the C12 different is the Carbon Fiber belt, it is stronger, it will not birdnest or string when it fails and it wears the clutches out less plus it is less expenisive than a OEM. We have sold hundreds of these with very few issues and all issues point to conditions not workmanship in the belt. Outside the cords in it, it is still a rubber belt and it is suceptable to damage from heat like the rest. If you made a belt that could handle a blow torch then it would not grip the clutches and it would slip all the time.

The reason for this article is to explain to you guys what causes these issues, let you fix them and be able to ride not work on it.

Also I can tell you Gates is constantly working toward newer and better ways to make belts. They have been around for 100 years but only been in the ATV/UTV belt business for a littlle while and they have already gained top position in aftemarket belts with this C12 belt. They will not stop there! I get to personally be involved with this process and test future products so rest assured Gates is in this to stay and so is Hunterworks!!!

If you need any help with clutching and help with trying to figure out what is going on with yours then feel free to call or e-mail

Todd
 
#3 ·
You said that running in low range allows the belt to run higher in the primary for better grip etc. I always thought that high/low range was a function of the gearing in the transmission, and that belt position was a function of rpm's and the shifting characteristics of the clutch. What am I missing?
 
#4 ·
Low range/ higher RPM. Higher RPM/ Higher on the clutch. Higher RPM/ more airflow.
Your missing nothing.
 
#5 ·
I agree with all said! I got about 1200 miles out of my OEM belt, but others in our group have had problems. And as you mentioned, it seems to all come down to heat. A lot of sand guys out west run with the clutch cover off as it seems to REALLY help the heat problem as you are at WOT almost all the time. I get tired of the added noise the clutch creates when the cover is off so have been running with it back on lately. I wonder if some type of 12V blower (like the ones used on boat engine bays) could help the situation. of course they are noisy themselves.

basically wondering what your opinion is of running without the clutch cover.
 
#9 ·
Great write up..
I agree with what you have stated. And looking forward to the new Belt Temp Gauge. That should shed some light on things.
I have always ran a stock OEM belt on my units. I change the belt once a year during my annual tear down and service. The mileage on my belts runs between 3500 to 6500 mile per change. And I have never lost a belt yet. But I do carry a spare just in case.
And I do try to use low gear as much as possible.
As for the Gates C12 carbon fiber belt, it has my interest. But so far the OEM belts have stood the test of time for me..
 
#13 ·
I saw a clutch cover modification somewhere online where they cut some holes through the cover and inserted some mesh fabric of sorts to keep out debris. What would the benefits or subtractions be?
I would assume water could get in there, as well as fine dust. Also it would be louder. Any thoughts would be appreciated.
 
#17 ·
I just put one of Todd's C12 belts on after 2150 miles. The stock belt had seen various conditions from open desert to Moab. I had smelled it heat up a few times and it was glazed over and worn unevenly kind of like a tire will with a bad alighnment. It was obviously due. I was surprised at the "feel" of this brand new belt, my XP is snappier.

So Todd, it there such a thing as "belt break in" or can it just be driven normal (hard) from the start?
 
#23 ·
I find myself in belt hell all of the sudden. Everything posted here is obviously correct to me in the evidence I have seen. I have owned my 900XP 4 for a year. I run smaller than normal paddle tires in the summer for Silver Lake Sand Dunes. 26.5 x 11.50s in the rear and 26.5 x 9s in the front on Douglas wheels. I shaved 15 lbs per rear wheel/tire in on the back and 11 lbs per wheel/tire on the front over stock. The machine runs so much better in the dunes. I snapped my first belt in the dunes. I had smelled the belt getting hot a few times prior to it blowing. When I changed it, I found that it was an EPI belt that was installed with the clutch kit. OK. I was hot rodding in the dunes, doing hill climbs. And, that belt had a full winter on it before then. And in the winter, I run Camoplast Tracks. They are a lot heavier, no doubt, but they have about 30% gear reduction built into them.

I replaced the last belt with an OEM Polaris belt. 5 Trips to the dunes riding at about 5 hours with breaks since then. Now it is winter and we have TONs of snow this year. I took the machine on a 44 mile loop with tracks in snow. The first half of our journey was pretty easy, groomed snowmobile trails. The second half of the trip, the ORV routes were not groomed and we had some deep snow. I had been smelling belt basically all day.

So after making it through a pretty brutal area with deep snow, we made it about 2 more miles down the trail when BAM, the belt gave way. I honestly thought the machine was on fire there was so much smoke. I had a spare belt with me. Thank God since we were 11 miles from the nearest road in the middle of a pretty heavy winter. When we pulled the clutch cover, there was no belt. It had completely melted and wadded up and the primary and secondary pulleys. We had to let the pulleys cool for about 30 minutes (in sub 20 degree temps) before doing anything - they were so hot, they melted our gloves. We slowly pulled belt pieces out of the pulleys piece by piece for about 30 minutes. There were belt strands clogged into the secondary that we could not get out, so we installed the new belt and then drove down the trail, and pulled the cover back off 2 times slowly having the machine help us get the debris out.

First problem here - Because of the crazy amount of snow, the intake filter on the belt induction system was a frozen ice cube. I just took that filter out entirely for the rest of the trip. But, now I do not know what to do. The filter was also totally falling apart. This is a 2012 with 1000 miles on it. (on its 3rd belt). Anyway, the frozen ice cube for an intake filter was obviously inhibiting any airflow at all and that probably led to a mass build up of heat under pretty heavy duty conditions.

Second issue - This is the second time I have blown a belt and both times, the primary and secondary clutches were so hot, you could light a cigar off them. I have to assume that heat probably damaged the clutches? Time for a clutch rebuild?

Third issue - I bought this machine from a dealer used, but also already "fixed up". It has a Yoshimira RS-4 pipe and header system, a Dyno-Jet Power Commander, and an EPI Clutch Kit installed. The dealer did all the work. From a performance standpoint, I have no complaints about the current clutch setup. This machine performs very well on tires and tracks. But obviously, this clutch/belt/heat issue is serious and I need to solve it.

Question - I think this is the same question a lot of people that have had belt issues would ask. Is there a way to promote airflow to the clutch cover. I want to leave the filter out as even a brand new one seems like it would inhibit airflow to the clutch. I agree that it seems like a forced air system would be in order with how much heat can get built up, but, Polaris would have done that it seems.

I don't know hardly anything at all about CVT clutch systems. This is the first machine I have owned that had one. But, I used to be a dealer auto tech and have raced and wrenched on motorcycles, cars, hot rods, etc my whole life so I am ready to get this figured out so I can tune and service this system myself. I would be grateful for additional tips and direction on clutch tuning and solving what I think is premature belt failure due to heat.
 
#25 ·
I don't know hardly anything at all about CVT clutch systems.
Vail, You are putting tremendous load on that transmission system. It sounds to me like a clutch tune is in order per-track install each winter. Personally, I'd best be getting to know your CVT ASAP.

Thankfully you had a belt and was able to get it running again. That could be a serious life threatening situation (as you clearly know). This is supposed to be fun, not taking your life in your hands 11 miles into the snow. Damn lucky and smart to bring a belt and the tools...

Start reading about CVT so you know what people are talking about when they give you advice. You don't need to be an expert, but you do need to know how it works, what the basic components are, and what general impact weight changes will have. Then you can modify to your heart's content and dial it in for your specific machine. Everybody's setup is different.

There are some excellent write-up on the forum.
 
#24 ·
I am not a EPI clutch kit fan at all but I can't say for sure if it is causing you a problem. I suspect you have a higher than normal stall speed.


Sounds like air flow is your biggest issue, riding slow and high loads are causing you issues too.

So keep it in low range, keep the intake for CVT clear and add the inline fan for added flow.

Then you might want to consider a Dalton clutch kit.

Since you are burning belts, give these Gates C12 a try, they are a great belt and the price is right. PM me on that

Todd
 
#26 ·
Oh, I'm not a risk taker. I had tools, food, snow shoes, 4 extra pairs of gloves and was dressed for the arctic despite the fact that it was a very warm day (in the 20s, that is pretty warm for us this time of year in Northern Michigan). We had phones too. This is also a trail system I have run and reconned many times on tires/dirt prior to doing a winter expedition, so I did my homework. I also had both GPS and paper copy maps with me. But, I do all that planning so that, as you mentioned, I don't need any of it and it is a fun day. This day was tough day because I also hit a tree stump under 25" of snow and bent one of my front lower control arms. It was drivable to complete the trip, but needless to say, I was fighting the wheel for the rest of the day. Anyway, a lower control arm is simple, bolt it on, do an alignment, and hit the trail. The CVT belt and heat issue is more of a concern to me. These things are made to handle tracks, lot of people run them, in more treacherous conditions that we are in. Polaris makes tracks for them as well. There is 30% gear reduction in the tracks and the tracks are geared to the motor and transmission system for the machine. Tracks are awesome by the way, if you live in a snow covered landscape.

I have done quite a bit of studying since the weekend and the CVT clutch system is actually very simple, simpler than I thought. I have worked with a lot of centrifcally actuated systems or gyro actuated systems in the past with a lot more moving parts! These are a little simpler. So when I say I don't know anything about them, I guess I mean I do not yet have a lot of first hand tuning experience which I soon shall get. Ordering the clutch puller today and the clutches will come out. Mostly I want to investigate the intake and exaust system for the housing to make sure they have no restrictions. Then I want to make sure the clutch assembly (primary of most concern) was not damaged due to the heat.

I also notice that the foam seal around the clutch cover was broken and the lower half was missing. I have seen other people and videos where they mentioned the same thing, like it is a problem happening during assembly at Polaris? Despite that, I had no water in the cover. But a good thing to check for next time you have your belt cover off.
 
#27 ·
Well, I have started working on a few solutions for my belt woes. I ordered a 3" bilge blower (normally for boats) to run in the intake duct for the CVT housing. A lot of guys are trying this. A lot of people are saying "working great so far" but there is not a lot of conclusive evidence that this is a sure fire heat fix with no more belt issues, etc, though I would think it would work great. A lot of race teams do this. I think we all agree that more air at all times is better. In keeping prepared, I actually ordered two. One to install and one to keep in the tool box as a trail backup just in case. I also ordered the SLP pre-filters that replace the stock pre-filters. These rivet onto the body and are made of the frogskin material that all the snowmobilers run. This will eliminate the stock pre-filters and hence keep from turning into ice cubes. I read a review of another tracked Rzr that went to these to solve the frozen pre-filter problem with good success.

I also ordered the clutch tools to get my clutches off and get them apart to finish getting belt debris out and inspect and clean them. I guess I will go from there. Hunterworks - I was reading a bit about the Dalton Clutch. I like the adjustability without pulling the primary off. I also need to just study how the dealer set up my current EPI and see if I can tune what I have. I also have a lot of interest in the Airdam Custom CV Tech clutch. This stuff is so expensive. I guess I need to decide if I want to keep pouring money into this thing or go back to racing motocross. The Airdam clutch is interesting to me because, according to the reviews and the guy custom machining these, he has gotten 81MPH out of a 900XP with a stock motor. What that translates into for me is more pull at the dunes on tires, and also more top end speed with the tracks, 55MPH or so on tracks. That would be a 10MPH increase and would make running tracks a lot more fun. Also, this Airdam CVTech Clutch is supposed to extend your speed range in LOW. I have seen reports of running up to 50MPH in Low Range. That would be helpful running tracks in deep snow as well because I need to try to and keep my speed up when going up hills in deep snow. The Airdam CV Tech clutch is a custom option and therefore pretty expensive, but when you are 11 miles back on the trail with 1 hour before dark in the snow and cold with a melted belt, that becomes a very reasonable expense all the sudden. haha. We'll see I guess....
 
#28 ·
My XP runs 80 with stock engine and stock clutch with Dalton in it, all I did was put the power commander on it to get a little more rpm.

Your EPI is not adjustable, you would have change weights to make any changes

The Dalton kit rocks!!

I won't comment on the other on a forum. You are welcome to call me and we can discuss any of this

Todd
 
#30 ·
Hey Guys, I did a little video of the many reasons I found for blowing belts. I actually then had to do a second video as I just kind of record these as I go and as I am finding different things. In this video I state that I was going to run the CVTech Trail Bloc clutch from Airdam. Not sure about that anymore. i have found so many other reasons why I could be having trouble that I am going to remedy the acual failure modes I have found first and improve the CVT Air Intake system, and then wait to see what results I get. Anyway, perhaps these two videos may be helpful to others looking for information. In my case, I had an engine to trans bolt broken causing multiple problems as well.


 
#31 ·
Hunterworks, is the Secondary replacement that you carry the Team Industries factory secondary? Exact same as stock on the XP? I secondary sheeves have alot of nicks and I think I might replace the entire assembly. Let me know. Thanks