Belt

 
Belt - Deflection adjusted highest and belt still low
Belt - Gap between belt and primary sheaves?
BELT - Application Chart - Dimensions & Part Numbers
Belt Deflection recommendation and video
Deflection cam at #6, belt still low
XP / Rev 800 Belts
Belt Temperature Limits (belt death sentence temps)
Aftermarket vs. OEM belts - regarding rpms at full throttle
Belt - Blowing and both clutches hot
Aftemarket vs. OEM belts we tested (heat durability)
My Freeride 137 is blowing belts

 

Belt - 800 belt on a 600/500SS - Don't do it.
Question) I hear about putting an 800 belt on my 500SS, will it last longer?

Answer) Don't put an 800 belt on a 600 clutch. An 800 primary has a forged sheave. The 600/500SS is a cast sheave. The 800 belt is a harder compound belt and is designed to run on a forged sheave. The non-800 belt is softer compound and designed for cast sheaves.

What happens is the 800 belt will eventually wear a groove into the sheave at the "shift range" that you normally drive at, literally putting a dished groove on the cast sheaves. Some racers use an 800 belt on a cast sheave because it allows the engine to accelerate quicker from engagement rpms to peak rpm. I would not advise that kind of blend on a consumer sled.
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Belt - Deflection adjusted highest and belt still low
Question)One other issue I have is that the belt height adjustment in the RER secondary is maxed out even with a new belt and it is still slightly low. Is there a fix for this?

Answer)Yes there is a fix, rather an adjustment. Open up the secondary, there are 2 shims inside of it and can remove one shim then re-assemble and re-calibrate the belt deflection.
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Belt - Gap between belt and primary sheaves?
Question) How much of a gap should there be between the Primary halves and the belt? this is sitting without the engine running with the belt pushed to one side, how much of a distance should there be between the edge of belt and the primary sheave?

Answer) With a new belt on at 1.48 inches, anywhere from .020 I have seen up to .080 inches. I believe .050 with a new belt is about average (my experiences)


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Belt - Application chart - Dimensions and Part Numbers

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-Belts can vary in length 1/4" -+ from spec. Years ago I measured an 8607 that was 5/8 inch longer than spec.
-Owners can choose belts with different lengths - refer to the Skidoo belt application chart above.

The video I linked what I set mine like or any other sled up for good all around deflection. What you are doing by setting this kind of deflection is eliminating a calibration problem that can come from the varying belt length. You are making sure that the right tension is going to be measured regardless of belt length or width.

The sled is with the track off the ground. Engine idling if the track can turn slowly or the track jerks a little bit, trying to turn, or does not turn however you can grab a track lug with your index finger thus pulling the track around - all while the engine is idling.

On the mxz/rev chassis with HPV secondary (RER) as the cam number increase, the belt tension will get tighter.

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With this kind of deflection in the video linked below I never let my engine idle too long. There are 4~5 cogs wrapped around the stub of the primary and the temperature gets high localized in that area. Excessive idling contributes to why belts will blow about 4~5 cogs off and you hear that "puk puk puk" just before the belt incinerates.
The temperature in that localized area will change the composition of the rubber making it a harder material; eventually separation will happen....BoOm!


 
 
Deflection cam at #6, belt still low

IF the belt defleciton cam is on #6 and are not able to get the belt to ride up in the secondary, THEN you can 1)remove one shim from inside the secondary.  2)Reset the belt deflection cam back to #1 position.  3)Peform belt deflection procedure again.

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Click for Deflection video


  800 Belts
About the belts - If you stay away from the 414300 383  that would be great because of the known rpm inconsistencies when running the sled hard.  I only recommend the 391 from the summit xp 800

If you buy a kit off of me, don’t call or email me if you have problems using the 383 belt, I am not hearing this argument as these belts reveal the same two results all the time before they explode, im not explaining about it other than saying, "fail" for anybody who has above capacity aggressive rider and you do not have secondary clutch bushings with diameters that are near or at the wear limit.


The 417300 391 is the best belt for my kits.   New belt, clean with the hottest water your hands can handle and green 3M scotchbrite pads to rub that release agent (sticky stuff) off the side of the belt and it won’t rpm correctly until about a tank of gas is through the sled; glued belts take a long time to take a “set”

391 - I do not have a problem with the 391 belt.  What you the driver will have a problem with is if you are running hard enough in the snow that the belt eventually gets to its temperature threshold and then….BOOM.  So I don’t know how hard you run, but [breaking trail/lot of time at full throttle/low speeds/high loads] heats the drive belt up. 

Another great belt is the 417300 288 from any 600RS, they both have great quick rpm response. I do not recommend the 383 anymore. I have had too much fluctuating rpm problems with it and so have many of my customers.

Note: Whatever belt you can get, try to get your hands on them yourself to measure them and make sure they are at least 1-7/16 wide, prefer 1.5"


 

Belts we tested - heat durability

If you are tempted to run an aftermarket belt, we have had great performance with the older Carlisle XS belts.  Note that calibration flyweight compared to the BRP belts, with the Carlisle belt you would observe 1gram lighter to get the full throttle rated rpms.

800 Summits
XS821 43-15/16(43.93) 1-33/64 (1.515)
XS821 is a shorter however wider belt than XS803

800 Trail sleds.
XS803 44-7/32 (44.21) 1-7/16 (1.4375)

The newer Dayco XTX and Goodyear Powestreak belts - we got to test them and give all the belts back to the Reps.  On our particular setups, they just run hot and no warning when they fail, no chord come out, just ....boom!

I would still rather one run the BRP#417300391 drive belt for longest belt life and ability to handle high temperature cycles.


Belt Temperature Limits (belt death sentence temps)
Belt temperatures I've personally measured on 163's and 154's
The 288, can take up to 195 degrees, at 200 the chord will start to work its way out.
The 166 / 391 can take up to 185 degrees, at 190 the chord will start to work its way out.
The 383 can't take any heat, it just explodes when run hard after 160~180 degrees.

Color on side of drive belt - Take a look at the angled side of the drive belt.  Notice when-new that the color of the surface has a green tint to it.  That green tint can be used as a color indicator of when you are at the high-limit of the belt temperature.

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Example 391 drive belt - the drive belt will reveal a green tint on the side of the drive belt up to and about 175~185 degrees.  Once past 190 degrees the green will fade out and now black color will be observed.  You get the side of the drive belt to that black color and it stays black in color then that is an indication you have overheated the drive belt.

You can take 3M scotchbrite pads to wash away the black deposits.  The side of the belt brightens up, however once at that black color, even after cleaning to green, we noticed the black color quickly return even 10~15 degrees below the failure temperature. 

The black color suggests the belt is ready to fail when its temperature approaches the upper limit – it's just a matter of time at raised temperature to failure.

Beware of climbing that chute to where you need the belt to be at its best, personally I would not use a belt that keeps revealing the black color.  What I mention above is only MY observations and not "advise", rather I am only explaining what data I have personally recorded with me and my great test buddies.

Other belt brands ...Have you tried the more economical carlisle 821 or gates 43x4320 Xtreme - use the summit xp belt even on the REV chassis.
The Gates data sheet says to 230 degrees.  Follow Gates guide on how to break-in properly and allow the new belt to conform to the angles of the clutch sheaves, which will allow for greater more stable output of power to the track.
You'll find that the gates belt reveals the same quirks as the 391 in the first 1/2 tank of gas but once broken in and taken a "set" then the rpms will come around and be stable and easy to calibrate.

When a chord starts to pop out, snip it off and push the chord back in the slot, then burn the rubber with a match or torch to try to encase the chord again.  (i got this information out of a 1996 BRP 440 race manual)

When running a certain drive belt, try to have the spare belt as the same model (don't mix n match) if you can help it as to keep the full throttle rpms the same regardless of the drive or spare belt use.

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Aftermarket vs. OEM belts - regarding rpms at full throttle .
The rubber compounds of aftermarket belts are generally softer than the original BRP drive belt.
IF you were running the BRP belt and observed your rated rpm (example 8000) and THEN change to an example Carlisle XS803 belt, [reset the belt deflection if required or if you can] and go out and run the sled full throttle.  You will observe 7800 rpms at full throttle.  The softer compound works harder against the sheave thus causing lower rpms.

What do you do about the 200 rpms loss.  1)change flyweight, or 2)increase clicker number.
 
Full throttle looking for about 8000 on the tachometer.
Observed 200 rpm lower (7800) at full throttle

Theory
1g = approximate 200 rpms difference.
Need more rpms = reduce pinweight
Need less rpms = add pinweight.
 
Example: If you needed 8000 and have 23.5g pins installed.
You run and reveal 7700.
8100 – 7700 = 400 rpms.  1g = 200 rpm change.
23.5g – 2g = 21.5g
And go out and do a full throttle run again.

Theory
1 clicker number = approximate 200 rpms difference.
Need more rpms = raise clicker
Need less rpms = lower clicker

Example; if you needed 8000 and observed 7800 while in clicker 3
Then change to clicker 4 and go retest at full throttle.

For mountain and backcountry riders who want the belt to grab hard in the trees and lug the engine to prevent the track from trenching, then can go to a softer drive belt whether it be a BRP or Aftermarket.  The softer belt will reveal a more "Squishy" throttle feel, when crawling through the trees.  This commentary has been gathered from many tuners.

 

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Belt - Blowing and both clutches hot

Question) I went out today with the stock pipe on my So-n-So-Summit.  14.5g, bang on 7900/8000, clicker 3, track speed 42mph at full throttle, 20:49 gear, new Peak 2.5 track. 
Had an issue.  Belt blew, both clutches were extremely hot.  Belt was 1.43" wide at the top, set it per defection video.
Wondering if I should drop from 20t to 19t in order to compensate for the Peak 2.5 track.
Power felt good today and if i didn't blow the belt i would have had a great day.  I worry if i can't get the heat down on the clutches i am just going to be blowing belts all year.

Answer) Belts blow due to; 1) misalignment, 2) clutch bushing fitness(out of parallel sheaves), 3) incorrect flyweight/clicker calibration (fluctuating rpms) and 3) time in seconds spent at full throttle (overheating)

Check the engine mounts? Are they hard, broken, loose?  XP's double check the E-Module under the primary (pto side) for cracks, and the front pto mount for cracks.
Check the clutch alignment.
What are the 2 primary clutch bushings and secondary sliding sheave bushing like for size and fitness?
What belt deflection is being used is it correct? (you noted great deflection)

If bushings are great, flyweight reveals 7900~8000 (correct rated rpms) and 70 seconds or less at full throttle, then ideally the belt should not blow unless misalignment is causing overheating. 
Check the color of the belt after a decent pull of less than a minute, even 40 seconds will do to get some color into the sidewall of the belt.
IF you still observer decent yellowish/greenish or greenish/yellowish color on the side of the belt, then you are less than the death sentence temperature of the drive belt.  Once the belt is turning hot enough to change the color darker brown to black, and you know that from checklist #2,3,4 are all good, then I would point my finger to be #1(misalignment).

Misalignment is something you have to check yourself.  As each year has rolled along since 08, BRP has kept coming up with new alignment specs and finally an outright relief to a demand making a floating type secondary clutch.  They are saying for "lightweight".  I don't buy that; then make it a solid lightweight shaft in the first place. 
The newest shafts being made 3mm (.125” ) longer from the bearing location to the back of the secondary sheave than the previous years AND different again, alignment specs.
My 08 sled was one of the worst alignment problems I ever seen, I had to use the additional shims that the doodoctor recommended to straighten my belt out.

If you keep an eye on the temperatures and the engine mounts are good, frame under engine is not cracked…then that 377 could literally last the whole riding season.
If you still have problem with belts after checking these details then the alignment must be questioned.

-----------so after all that is said, then watch the color of the side of the belt after you clean it before you go out.  take note of the color.
When you are running in the snow now, count the seconds at full throttle and say when you get to about 25, try and turn out or if you can, stop safely and pop the side panel, get the cover off and have a look at the color of the sidewall of the belt.  Keep a mental note that "i can run 30 seconds and not overheat"  ok, next time you go out, get another 10 seconds under your belt (total 40) and do the same thing.

We were getting 70 seconds at 38mph track speed in revelstoke and still able to maintain noticable color on the side of the belt, running our etec at 7900~8000 rpms.

Here is a clue that your belt is getting near the temperature limit.  When you are at full throttle and maintaining 7900~8000 and watch the track speed holding (example 40mph) When still at 7900~8000 all of a sudden, you see 39, then 38 and stays at 38 but the hill is not getting steeper - give it a few more seconds - stop and check the color of the belt, I have no doubt it will be dark.

Belt Tempurature & Gearing:  We have been testing lower gearing since Jan 2009 with the 49 and 51 gears. We know that any lower gearing gives track speed staying power and enhances resistance to load changes while at full throttle.  Gearing lower allows the drive belt to move across more of the sheave face surface helping the aluminum extract away more heat from the belt.  The belt spends less time in a certain position as the load changes while at full throttle.  BRP knee jerk reaction for years for customers on warranty belt issues has been to lower the gear ratio and look what they have done in 2012.  146@ 21:49, 154@19:49, 163@19:51 and to me personally I have tested those gears in earlier models in 154/163's and there ain't anything wrong with them - my clutch kits work excellent with the lower gearing that what people are normally pre-programmed to run.

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My Freeride 137 is blowing belts

The belt heat rises when you are running much full throttle in deep snow.  The rear end of the sled goes far into the snow, augering. 

The angle of the 137 sled cutting through the snow is steeper than a 146, but less steep than a 120 sled.  The more the angle of the sled, the more cutting of fresh snow, adds more heat in your belt – Save your belt and gear to a lower ratio.

My own 800e x 120 x 2” has 21:49 (same as 19:45) and now I put more full throttle cutting fresh snow at 8000~7900 than I've ever done before and had lower belt temperatures.  With the 23:49 I was still overheating the belt.

Any time you are on the throttle, augering through the snow with skis in the air – your sled is in a constant climbing state.

The Freeride having a more stiff suspension than a BCX or Regular Rene w/1.75, there is little to no suspension movement once you have good track speed going cutting deep fresh snow.    A regular Rene with its adrenaline suspension is faaaaaaast in the snow as their suspension follows the contour of the fresh snow more fluidly.

Blowing belts on a Freeride 137?  Soften the suspension to react better to the vehicle speed going through the snow and cause less augering angle and less lifting of the front end.  Turn all springs down to a lesser force.

When you spend more time at full throttle in deep snow the belt gets hotter.  Give the belt a break and gear according to what you are putting the belt through.  Higher load use, lots of cutting fresh snow = gear lower

Always think about the belt, treating it belt properly through correct gear ratio that allows a lot of time at full throttle.  That means gear down if your time in deep snow goes up and starting to blow belts.

If you are at 23 top with 1.75 and blowing belts from overheating then go to a 21 top and it will extend your time at full throttle in the snow.  Belt temperatures will raise slower.  If at 21 top gear you are still blowing a belt, but getting better mileage and time-out of it – gear down to a 19 top gear.

The belt is the connection between your engine and throttle.  Gear down according to the load increase you are applying to the belt. 

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