Has there been a head to head comparison on the rage4 against polar Like track dyno or in the field does one put more power to the ground?

Howard Haacks record run was on a STM 4 arm clutch today

Dave Dunn sent his STM out to ebay, and got rid of it. What does that tell ya.

haack breaks a record on his impulse powered turbo, hallnracing is running in the mid to high 60,s on the tar, fuller and the osp sleds are breakin into the 70,s on the tar , the 1 thing they all have in common is there being powered by stm clutches , what does that tell u??????

Nothing, it doesn't tell me a thing. Is that what you are running, or do you still have the Polar?

Kevin, you of all people should know that each clutch reacts differenly on each individual sled. The STM clutch is a VERY nice piece however it just did not perform as well as some of the others did on the dyno on this 1200 4 tec. Thus the reason why the Polar was chosen for this particular build.

thanks for the clarification dustin, the way kid rocker posted , im sure u and dave will agree that it can be interperted a couple of different ways,

I'm not picking on anyone's tuning ability as we know the polar is very simalar to TRA to tune - but clutches have to be tuned differently as well and maybe not enough time was spent on the STM. There has been great sucess with them with many different tuners, showing awesome results. I would not write them off as a clutch to be used on the doo, they make awesome products.

Robbie

Well here is what I was actually trying to say Kevin. Clutches don't make world records, tuners do. I know for a fact that the STM does not put the hp to the ground like the polar does on the Ski-Doo 1200. That is a fact, ask Brent Hoag. So for someone to say that world records are made with the clutch they use is somewhat factual. You still have to tune the clutch. But on the 1200 I would bet that most people will go with the Polar clutch #1 for hp to the ground, and #2 the cost is about half. Many ways to accomplish the same results. Not trying to start a war, just posting facts. The reason Dave sold his STM was because it would not put the hp to the track like the polar clutch does. That is why I posted what I did. The STM clutch is a very nice clutch indeed, and many people run it. The question was about clutches on the ski-doo 1200 originally, and I probably should have posted this post to begin with. Sorry for the misunderstanding on my original post.

What is the sheave angle of the STM versus Polar???????? They are not all the same and none of them are the same as a TRA.

Also what is the sheave angle on the SkiDoo secondary???????

What is the sheave angle on the TEAM secondary?

Been hearing nothing but good things about the Polar clutches. Even though I am running a stock sled, I am still thinking about going with one of the Polars. Does anyone have a baseline set up for the polar for running it on a stock sled? I am only about 2 hours away from Dunn, so probably could go through him, but just curious for some opinions.

Iv asked this before but never really got an answere, how is the polar diffrent from a tra ? it uses ramps,arms with rollers,adjustable weights whats the diffrence besides its billet ?

Not being able to have both apart from the looks of it the TRA has a longer ramp for roller contact,
due to location of the ramp in the clutch of coarse.
The Polar IMO (and Now going to date myself a bit )mirrors the Arctic Hex clutch of days gone by.
Which was one of the most tuneable clutches I have ever dealt with.
Probaly not the answer you are looking for but at a glimps the first things I noticed.

Completely different use of the same stuff. For example you can run the Polar without the spring, I've done it. Try that on a TRA! It is the only clutch I have found that can do that.

It is also an extremely stable clutch. I have ran it from 3,000 feet to 8,500 feet and the rpm doesn't change. A local 1200 turbo ran the 4 post Polar and the clutch had no issues.

I'm waiting for a 4 post Polar to run on my 800R this year. We had to add too much weight to the 3 post model and were killing the arms, the 4 post uses less weight per arm.

I have also used the TRA, Polaris and Comet primary's on my 800R, and I keep coming back to the Polar because it is just too big a difference to not go for it. Mountain riding is where you really notice the diffence between the clutches. You can ride around your house on just about anything, including a 250 hp monster, but when the motor is flat out and you are hanging ten, you notice things like clutches that put the power to the snow.

Do I sound too demanding?

[quote name='YamaDooPolCat' date='Oct 16 2009, 11:42 PM' post='2492427']
Completely different use of the same stuff. For example you can run the Polar without the spring, I've done it. Try that on a TRA! It is the only clutch I have found that can do that.

It is also an extremely stable clutch. I have ran it from 3,000 feet to 8,500 feet and the rpm doesn't change. A local 1200 turbo ran the 4 post Polar and the clutch had no issues.

I'm waiting for a 4 post Polar to run on my 800R this year. We had to add too much weight to the 3 post model and were killing the arms, the 4 post uses less weight per arm.

I have also used the TRA, Polaris and Comet primary's on my 800R, and I keep coming back to the Polar because it is just too big a difference to not go for it. Mountain riding is where you really notice the difference between the clutches. You can ride around your house on just about anything, including a 250 hp monster, but when the motor is flat out and you are hanging ten, you notice things like clutches that put the power to the snow.

Do I sound too demanding?


No, not to demanding at all.

But when you speak about your clutches and say you can notice them, it's no different then when us flat landers when we are running upnord style ,drag racing or radar running.

I guess my point is if you know your sled you can feel when things go Soggy(heat,reduced speed,lag in acceleration,etc).

For us race crowd we feel the clutches in 10's and 100th's of seconds.

Cliff yeatman

Wow! Everybody missed my point. How do you run stock SkiDoo belts when the sheave angles are different? You can use any clutch for racing with enough testing so I am not sure that points to the correct clutch combo for a trail sled.

Actuallly was waiting for Someone to post the angles of these different Clutches.
The Blue Max has a valid point for the trail applications.
Are these 1000+ mile trail clutches with Boost pushing them?

The stock TRA primary starts at 24^o and then finishes at 28^o. The stock TRA secondary is 28^o.

The TEAM secondary per TEAM is 29^o. I don't know what the other 2 manufacturers use for angles and they may even machine to customer request.


Changing the sheave angle affects belt requirements to maintain original top speed. Unless clutch centerlines can be changed, belt length will become an issue. Drag racers will alter these parameters to use whatever clutch they desire. These parameters are more important to trail riders that expect to bolt on and ride without issues.

Steve,

Stock belt will work fine, just have to adjust gearing to get the speed you want. I don't know what all the clutches are but most primaries are in the 13-13.5 sheave angle range. The larger dia. ones run less angle and sacrifice efficiency by doing this pinching the belt too hard up top. Aftermarket primaries will not have the overdrive like the TRA unless they are the inefficient large dia ones machined with less angle. Shift ratio is not as important as efficiency. New technology and innovative thinking allows us to use standard angles and size clutches on very high HP race machines. The trail stuff is easy. 10-12 percent overdrive is the most common in std dia. clutches with 1 3/8 belts.

That was kind of my point. It may take a few more mods to match the overall stock clutch performance parameters. Some expect to just bolt on an aftermarket clutch and their performance will be instantly improved.

Instant performance. Sometimes yes, most times you have to work for it. The ones that don't know how to tune soon sell the stuff.

We'll have another option very soon

nice! cant wait.

Very very sneaky, nice Kevin, hows your boosted 1200 coming , call me and I can fill you in on what I have learned to date

Cool clutch CS1006. Is that gonna fit the TRA IV or Completely new entirely?

? for the STM clutches. They offer 8, 8.25, 8.5" diameters for the Rage IV and even bigger on their Rage VIII. Is there a happy medium between stock size and larger ones?

The pic shown above will be based off of the TRA 2 and can use OEM spring cup, splined gov. cup and all OEM hardware. maybe a billet gov cup next.

a tra 2 has a wimpy shaft and spline
no way it will take 4 stroke torque
it will twist off at the governor cup

This picture is of a part I am building for drag racing, not a solution to a trail need. So far, the OEM shafts have been holding up just fine with some pretty strong motors. just how much torque does the 4 stroke have skidoo chris ?

I twisted off 2 with a stock RT using 285 ramps
1200 under boost is big numbers
400 hp @ 250 torque
300 hp @ 200 torque
a 1000 ps sled don't weigh much
and don't do low 1.2 60ft @ 800lbs
that is what my 1200 with me on it weighs and I weigh 200lbs

not sure i'm following your reference to our PS1000's and 1.2 60's ?? racing those on asphalt is a lot of finesse.

our big motor lake sleds are a little different and weigh 750 ish with me on it, 300+ hp levels.

if you're breaking clutches like that, especially on a stock motored sled, there's more wrong than a wimpy shaft.

when I grass dragged my Mach z 809's I liked using 285 ramps in a tra 2 and it worked well for me
well I had a few extra tra 2 just laying around so for giggles I stuck one on my stock RT
first good hole shot it snapped off at the governor, thought I had a bad clutch and tried another with the same results
I was not talking about any one PS1000 but most are much lighter than our XR's and the same weight as my RT
60 ft time is what drag racers use to gage their hole shot
the heaver you are the more HP it takes to get a low 60ft times

OK.
I do understand the drag racing thing.

As for snapping those off, not sure of the cause, maybe worn parts, twisted towers or ??

anyhow, good luck and hope your clutch issues get resolved.

Thanks, Jamie Bellman

Jamie, you sure you know drag racing? LOL!!!!!!!!!

Edit: Hey this just dawned on me, look left, its the last time I won Brainard. Does it still hurt? darn Yamahas! Couldn't resist

Perhaps the 4-tec need a fluid dampner? Weird thing is the TRA works just fine on a stock 4-tec all all RPM ranges. I have a hard time believing the TRA can't holt the tq. of a boosted 4-tec.

Ya, that pic caught my eye ( and made my stomach upset). That sled was just in a league of it's own.
The fluid dampner may be something to try, I still have a new one built for the skidoos, not sure how it will or won't mate to the 1200, you can try it if you want to.
I would like to see one of the clutches that has failed and measure everything in it, just curious. maybe i'll try to break one on my 1200 .

Busa747
sorry about waisting time on drag racing 101
your right they were old clutches with lots of miles maybe just bad luck
as for as me having clutch problems on my 1200 I am using a STM now
and the only issue I have is the same as it was when I still had the stock clutch on
IMO harmonics is causing my clutch to slip just a small amount
my crank always has a small malled up spot on it when I remove the clutch
I grind,polish and lap fit it but still have the issue
when I blue the fit it always covers about 3/4 of the crank and the 1/4 or less is near the bolt

No worries.

with Knapp working on this, there will be a solution.

Might sound gay but just a thought, would some redlock tight be enuff to work/help? Stuff works great under presure. Few drops on the crank? Would take 2 sec. to try.....

Skydog

if you use loctite how do you remove it

Clutch will not rotate if lapped in on crankshaft. Does not need loctight in that area. If you lap it on the crankshaft properly it will hold 500 HP using a 3/8 drive ratchet and not even tourquing bolt down.

Locktight is made to take up clearances and to hold nuts onto bolts, or hold bushings in.

It would work well to hold on a tapered shaft too, but would perhaps require some heat to get it to release using a puller.

I just can't imagine a clutch slipping on the crankshaft if tourqed properly.

A puller would take it off.

i can remember i had a 670 twin on asphalt with solid mounts that would regularly shear off spline on tra at the gov. cup. after installing a fluidampr no more broken clutch splines! im a believer in dampers!

Dave Dunn has killed the 1200 Doo all year on the tar with no problems?

Skydog

I agree. I would take a closer look at both the clutch taper and crankshaft. You wouldn't happen to have a pic of crankshaft after bluing.

no pixs sorry
I have heard horror stores of motors that had harmonic issues bad enough ruin the crank
as I said earlier I saw the same problem then the sled was stock

If this engine had harmonic issues happening it would show up stock. Belts would be blowing, rollers and ramps would be etched and have galling occurring, springs would break and casting would crack The clutch would basically disintegrate in a few thousand miles.

Chris, the harmonics I think you are referring to are all big two-stroke twins, race/stroker engines that run outside of factory designed RPM parameters that have not been balanced properly. This XR1200 is not one of them.

The XR1200 stocker show no signs of harmonic issues, just a drive clutch that wants to spin a governor cup on the stub of the clutch when turboed cranking out more than stock tq.

Chris, I don't think they understand your 1200 was rode last year in the trails for over a thousand miles in stock form (clutch had never been taken off). Upon removal (for the first time) the stock clutch galled the crank and it was worn. The stock clutch was never boosted period. That is when you went to the STM clutch. I would hope that Mark from STM knows how to properly lap a clutch as I watched him do it several times due to the galling issue. We don't really no what is causing it, it very well could be harmonics (engine is still a new design). Chris is just trying to inform you guys of some issues that are going on with his 1200.

Dave Dunn has been running his sled on the tar. From a business stand point I don't think he would come on here and say the clutches are galling the crank when he sells aftermarket clutches to people. Maybe he hasn't had any issues with this. This is not a dig at Dave in anyway just saying he seems to be a professional and would work to resolve the problem (if any) before posting it on an open forum.

As far as 1200's not having issues with the clutches, there are a few posts on clutch failures from stock machines.

Just observations from what I've seen with my own eyes. There is a lot of little problems we will all find on the 1200 when adding power, it is new to everyone (you wouldn't think by the way some people act). Just like the Yama's, everyone has to go threw the learning curve.

Interesting that it was galled after running all those miles stock. Gotta wonder about the clutch not being properly torqued right from brand new. I think this whole TRA clutch is to blame. Tapered governor cup and clutch shaft obviously requires some extra attention to get it to seat. Looks to me to be a poor design in the first place. But perhaps they should be checked for proper clutch bolt torque every 50 miles or so till you know they are seated once they've been off. That is why we lap clutches to the shafts, for the perfect fit.

Great stuff! I will watch mine close and Tq her more than one time! To make sure she is set.

Skydog

I've seen so-so fits on a few of these 1200's,I've got 2 polars and a comet 4pro coming for a few builds we are doing, I guess putting them on the lathe and checking there tapers against whats on the tra may give us some idea if it's a factory problem or just under engineered for larger hp.

Cliff yeatman