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Been doing some testing with our 2017 850 Renegade and also our 2019 850 Summit. Both sleds have been shimmed with our alignment tool and have our Poly torque stop.

2017 Renegade has holes drilled in the side panel in the same area as the 19 vent to help with air flow. I use a Razorback belt temp gauge to monitor belt temps, not measuring clutch sheave temps yet. Belt temp ranges from 125-140 most of the time, can get it up to 150 climbing in a foot of powder but you have to work it pretty hard. Once you get the belt hot and take it easier the belt temp will drop back down, something it didn't do before shimming. After running it hard and you stop the belt temp will go up 10-20 degrees for 15 seconds or so and then start to drop. This is telling me that the sheaves are warmer than the belt and it's the heat going into the belt as the sheaves transfer the heat to the belt. I'm measuring the belt temp when it is in the secondary. Once you start moving again the temps drop back down to the normal range. After 100 miles of testing I put Laflamme Racing clutch weights in the primary, only change. Overall the belt temp went down a few degrees with this change. Last year with the sled stock the belt temp would get up to 180 just trail riding 50-70 mph. Overall very happy with the results, hopefully everyone that used our tool is finding an improvment. Very little belt smear on the primary, last season had much more.

2019 Summit 154. Shimmed motor and installed poly stop before riding so don't have a before and after. First ride out the belt temp was 110-125 most of the time but the air temp was about 10 degrees. Clutches were nice and clean. Second time out belt temp was 120-135 and air temp was 30 so air temp really affects it quite a bit. Can get it up to 140-145 on long runs hard on the throttle runs Did more testing yesterday with camera looking at primary clutch bolt to verify work done with the Renegade, overall matched up well. Going to keep the .75" preloader load for a good spot to align the clutches. Did some cam testing without the clutch guard on and noticed a good 20 degrees higher belt temps without it. Temps went back down after putting it back on.

The Summit comes with a 531 belt which was quite a bit longer than the older BRP belts. I just got a Seek thermo cam to see if it would be a good tool to fine tune the clutch offset number. Thought was to take video of the secondary to see if one side was hotter that would be caused by the belt rubbing the sheave more if the offset was off. Put a couple links here, these are first tests with Summit, one is with 3mm shim in QRS and other is with 1.5mm shim. Overall the video gave more questions than answers and I think it will get some discussion going. It looks like the stationary sheave on the P drive with the wobble is causing more heat on that side of the belt. Some have mentioned that when they gun the sheaves the wobble sheave is always the hottest, could be from wobble or just it's getting all the heat from the crank, not sure. Need to do more testing to try and figure that out.


 

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After doing quite a few 0 to 80 runs my primary was 140 and the secondary 140 outer and 130 inner. Did not measure belt temp. 35 degree outdoor temp. Only had room for 80 mph and now the snow is gone.
 

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thanks for putting the time and effort, the inside sheave will always be warmer , so not necessary its the wobble..tra's were the same
 

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- pDrive, TRA, HPV and QRS -

Belt follows fixed wobble.

Movable wiggles to follow wobble.
 

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Wobble hotter than wiggle :lol:
 

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Been doing some testing with our 2017 850 Renegade and also our 2019 850 Summit. Both sleds have been shimmed with our alignment tool and have our Poly torque stop.

2017 Renegade has holes drilled in the side panel in the same area as the 19 vent to help with air flow. I use a Razorback belt temp gauge to monitor belt temps, not measuring clutch sheave temps yet. Belt temp ranges from 125-140 most of the time, can get it up to 150 climbing in a foot of powder but you have to work it pretty hard. Once you get the belt hot and take it easier the belt temp will drop back down, something it didn't do before shimming. After running it hard and you stop the belt temp will go up 10-20 degrees for 15 seconds or so and then start to drop. This is telling me that the sheaves are warmer than the belt and it's the heat going into the belt as the sheaves transfer the heat to the belt. I'm measuring the belt temp when it is in the secondary. Once you start moving again the temps drop back down to the normal range. After 100 miles of testing I put Laflamme Racing clutch weights in the primary, only change. Overall the belt temp went down a few degrees with this change. Last year with the sled stock the belt temp would get up to 180 just trail riding 50-70 mph. Overall very happy with the results, hopefully everyone that used our tool is finding an improvment. Very little belt smear on the primary, last season had much more.

2019 Summit 154. Shimmed motor and installed poly stop before riding so don't have a before and after. First ride out the belt temp was 110-125 most of the time but the air temp was about 10 degrees. Clutches were nice and clean. Second time out belt temp was 120-135 and air temp was 30 so air temp really affects it quite a bit. Can get it up to 140-145 on long runs hard on the throttle runs Did more testing yesterday with camera looking at primary clutch bolt to verify work done with the Renegade, overall matched up well. Going to keep the .75" preloader load for a good spot to align the clutches. Did some cam testing without the clutch guard on and noticed a good 20 degrees higher belt temps without it. Temps went back down after putting it back on.

The Summit comes with a 531 belt which was quite a bit longer than the older BRP belts. I just got a Seek thermo cam to see if it would be a good tool to fine tune the clutch offset number. Thought was to take video of the secondary to see if one side was hotter that would be caused by the belt rubbing the sheave more if the offset was off. Put a couple links here, these are first tests with Summit, one is with 3mm shim in QRS and other is with 1.5mm shim. Overall the video gave more questions than answers and I think it will get some discussion going. It looks like the stationary sheave on the P drive with the wobble is causing more heat on that side of the belt. Some have mentioned that when they gun the sheaves the wobble sheave is always the hottest, could be from wobble or just it's getting all the heat from the crank, not sure. Need to do more testing to try and figure that out.


cool stuff. I will throw something out for discusssion. the 3mm video shows slight less belt heat, more on the movable secondary side- may be normal as that side is slipping on belt more or it is picking up heat from stationary primary sheave, either way my initial thought would the 3mm is better. I know you have your own offset numbers for your tool but would you mind sharing what 3mm took you X measurement to?

Regarding your 2019 summit, that should have from the factory the stiffest mag mount offered, do you notice any primary clutch temp differences vs the gade?

Thanks for all the work you are doing.
 

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Jesus Daag, those posts were useless. Lol.
My own high tech hula hoop explanation to why the fixed sheave of the primary and secondary are hotter lol
 

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Anyone watch the videos to see which is better? I see one that looks better than the other.
 

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3mm looks to be slightly better, but the 3mm pull sounds to be slightly less throttle to the ear.
I was thinking the same. From the sheave angles one should be better than the other @ different positions of the belt in the clutches. So one should be better at higher shift while the other better at lower shift. It's still real hard to tell the difference between the two. That's where comparing extremes really helps, like adding a no shim comparison.
 

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I was thinking the same. From the sheave angles one should be better than the other @ different positions of the belt in the clutches. So one should be better at higher shift while the other better at lower shift. It's still real hard to tell the difference between the two. That's where comparing extremes really helps, like adding a no shim comparison.
Yes, need extreme of no shim and 3mm at trail cruising speed and 1000' full throttle pull.
 

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Yes, need extreme of no shim and 3mm at trail cruising speed and 1000' full throttle pull.
While we are at it, 20 vs 24 vs 28 wobble!
 

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Discussion Starter · #17 ·
I didn't do the greatest job at testing both videos the same, first time playing with the cam. I think the clutches were hotter for the 3mm shim test to start with so for overall temp that might be making everything warmer than the 1.5mm test. Plus the 3mm test was longer in time and was after doing some other testing. It took a few minutes to pull the QRS shim so everything cooled down, I did the 3mm test first and then the 1.5mm. I was mostly trying to compare the sides of the belt to try and see if the offset was making one side warmer than the other. Not sure it's going to work because the primary is heating one side of the belt more than the other by the look of it.

I have a short video of the first sled movement with the 1.5mm shim and the belt temp was more even. Seems like the difference in the belt side to side temp gets greater the hotter the clutches get.

 

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Nice addition! The even temp from side to side on the 1.5 cold video is what drew my attention for the first 20 seconds of the 3mm video under lower load including the more even belt when it stopped turning @ 41. The 1.5mm hotter video with higher load showed more uneven temp when it stopped turning.

After playing the first two videos side by side a dozen times it raised more questions than answers - I read that somewhere :lol:

- So what does this mean?

- A 1.5mm difference in the QRS isn't all that much when the clutches are already aligned in the horizontal and vertical planes?

- Are the QRS shims more important when the horizontal and vertical planes are out of alignment?

- Fixed pDrive sheave generates a lot more heat under higher loads?
 

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The primary is the source of the heat, more importantly the fixed. It would be of value to measure each primary sheave temp at with different shimming of the secondary. My theory would be that improper offset of the Qrs could create a much hotter primary sheaves, proper offset may reveal a much cooler sliding primary sheave vs fixed, the fixed is picking up engine heat, proper alignment and offset should help minimize.
 
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