Skidoo 850 Etec Offset Problems - Exploding belts

[bcpowder84]

I had a 2013 Cat that was exploding belts into a million pieces, without any real signs of wear before they blew. Clutches were hot after long pulls, but not out of this world. Heat would generate in the belt more than the sheaves. These two things happening generally point to an alignment and or offset problem. Heat from slippage will generally de-laminate a belt, and generate huge heat in the sheaves, but doesn't usually explode them without significant signs of wear first. i fixed my cat belt issues first by correcting the offset, and a slight adjustment to the parallelism of the primary and secondary.

I now have a new 850, and i have blown 3 belts in 400 km. I am very diligent in keeping my clutch compartment clean, heat cycling belts for break in, and generally keeping a close eye on the health of my clutches and belts. BRP has told me that there is nothing they can find wrong with my sled, so i took it upon myself to get a hold of the service manual do so simple checks my self.

As it turns out, my offset is out of spec (secondary is too far out by 2.1mm, My x dim = 43.2mm, spec = 41.1, +/- 1.8mm), and the parallelism is only +1.4mm across the primary (skidoo specs the parallelism at 0 load to be at +3mm +/- .93mm across the primary to account for twist under full load). I have posted some pictures of the spec from the manual, and my sled's measurements in here for the rest of you to see. Currently I am unaware of a way to adjust the offset by shifting the secondary further in on the jackshaft as mine requires; however, I have seen shim kits to bring it out. BRP needs to address this issue and the only way to force them to do that is to put the spot light on it. I encourage all of you that are having issues as described above to check this spec on your own. Please add to this thread if you find out that your sled is also out of spec.

For a simple video on how to measure this spec check this video out. https://www.youtube.com/watch?v=FAHiyqZ1J98

X =

Y=

Blown Belt Problems clutch Issues Ski doo 850 E-tec etec E tec Skidoo Ski-doo clutching

 

[sick1]

Your going to have to correct it the hard way, loosen the four motor mounts remove the rear pto side one. on the xp and xm that one is static non adjustable the other three have a larger hole to move the motor around. once its out drill it to the direction you need the motor to move. re install and realign to proper spec. I always get the friday long weekend build of sled that eats belts for breakfast lunch and dinner. I've done it to 2 08s, my 11etec and my 13xm. Unfortunatly if you have a belt burner doo your on your own to fix it. the dealers will let it sit ... forever..

 

[bcpowder84]

Thanks Sick1...Is there any value in the floating Bushing for the secondary? would this be a simpler solution to the offset (not so much the parallelism)

 

[Teth-Air]

In 08 I had the same problem with my XP. I was told by the dealer it was all they could do. I had to float the secondary with the Doo Doctor kit to solve the problem as I already drilled out the mounts as much as I could. The G4 only has 3 mounts so I hope it is possible.

 

[Jgibos]

What is your belt deflection like? I had 3 belts go thwn really started paying attention to the deflection and its been alot better now.

 

[sick1]

The doo doctor floating or Qrs floating kits work but are spendy. Also i've broken three Qrs kits by having the sheave rip free of the hub at 500 bux each with 30 km on them with no warranty so i dont trust the doo fix at all. to me the motor mount is a better fix. I haven't had a chance to look at a g4 up close so i dont know if its possible to do the motor mount fix. Hope so.

 

[yada]

I had a 2013 Cat that was exploding belts into a million pieces, without any real signs of wear before they blew. Clutches were hot after long pulls, but not out of this world. Heat would generate in the belt more than the sheaves. These two things happening generally point to an alignment and or offset problem. Heat from slippage will generally de-laminate a belt, and generate huge heat in the sheaves, but doesn't usually explode them without significant signs of wear first. i fixed my cat belt issues first by correcting the offset, and a slight adjustment to the parallelism of the primary and secondary.

I now have a new 850, and i have blown 3 belts in 400 km. I am very diligent in keeping my clutch compartment clean, heat cycling belts for break in, and generally keeping a close eye on the health of my clutches and belts. BRP has told me that there is nothing they can find wrong with my sled, so i took it upon myself to get a hold of the service manual do so simple checks my self.

As it turns out, my offset is out of spec (secondary is too far out by 2.1mm, My x dim = 43.2mm, spec = 41.1, +/- 1.8mm), and the parallelism is only +1.4mm across the primary (skidoo specs the parallelism at 0 load to be at +3mm +/- .93mm across the primary to account for twist under full load). I have posted some pictures of the spec from the manual, and my sled's measurements in here for the rest of you to see. Currently I am unaware of a way to adjust the offset by shifting the secondary further in on the jackshaft as mine requires; however, I have seen shim kits to bring it out. BRP needs to address this issue and the only way to force them to do that is to put the spot light on it. I encourage all of you that are having issues as described above to check this spec on your own. Please add to this thread if you find out that your sled is also out of spec.

For a simple video on how to measure this spec check this video out. https://www.youtube.com/watch?v=FAHiyqZ1J98


https://www.snowandmud.com/attachment.php?attachmentid=203482&d=1488842645https://www.snowandmud.com/attachment.php?attachmentid=203484&d=1488842665https://www.snowandmud.com/attachment.php?attachmentid=203483&d=1488842659
X = https://www.snowandmud.com/attachment.php?attachmentid=203480&d=1488842638
Y= https://www.snowandmud.com/attachment.php?attachmentid=203481&d=1488842641

Blown Belt Problems clutch Issues Ski doo 850 E-tec etec E tec Skidoo Ski-doo clutching

Having major probs with belts here too. Measured mine last thurs with bottom pan off for better access. My specs are off too about the same as yours from both brp supplied specs for the summit and mxz x, mines a mxz x 850. I do not have a clue why the specs are different from the mxz x to the summit. Anyone??????
I do know the specs are also different from brp on the 800 etecs also from mxz to summit and on that other doo I have, the mxz spec had a major dogleg in it , I shimmed it out to the summit spec on that one and dogleg was gone. As far as motor mounts with three only it makes it tough to adjust brp design, but taking some measurements it seemed that if one was to shorten the mag mount 4 mm or so the clutches would fall more into spec. Just a thought. Was thinking of going with doodoctors floater but above post has me rethinking that now. I wish brp would come out with a fix, which they should.

 

[Teth-Air]

Having major probs with belts here too. Measured mine last thurs with bottom pan off for better access. My specs are off too about the same as yours from both brp supplied specs for the summit and mxz x, mines a mxz x 850. I do not have a clue why the specs are different from the mxz x to the summit. Anyone??????
I do know the specs are also different from brp on the 800 etecs also from mxz to summit and on that other doo I have, the mxz spec had a major dogleg in it , I shimmed it out to the summit spec on that one and dogleg was gone. As far as motor mounts with three only it makes it tough to adjust brp design, but taking some measurements it seemed that if one was to shorten the mag mount 4 mm or so the clutches would fall more into spec. Just a thought. Was thinking of going with doodoctors floater but above post has me rethinking that now. I wish brp would come out with a fix, which they should.

The Doo Doctor floating secondary was good for me, even moved it over to my 2011 XP.

 

[yada]

The Doo Doctor floating secondary was good for me, even moved it over to my 2011 XP.

Are you guys at source selling shims yet for the 850 mount??

 

[sick1]

The doo doctor is a totally different piece aside from the Qrs floating. I would do the doo doctor one if I had to do a floating kit again. I even did the team tied setup which worked well but I have better track speed with the factory secondary and dont want to buy more helixs and springs for the tied set up.

 

[cnelson6]

Racers edge has a shim built for the engine mount beside the primary to help with the flexing. Might be worth calling Daryl and asking him about that part as well.


Sent from my iPhone using Tapatalk

 

[chad006]

I run the team tss-04 on my turbo xm just finishing up dialing it in, its setup to float about 1/8". Same track speeds I was seeing with qrs except my clutches are relatively cool no matter the condition. Maybe an option on the 850's.

 

[Daag44]

Nice find bcpowder84! Considering crank and sheave runout, especially those who found the sheave misaligned on the shaft, this could this affect the X and Y measurements.

 

[Daag44]

0.6mm Clutch Offset can change Y-X Offset by 1.2mm

Now that we know the primary has a manufactured offset of 0.6mm, this could change the measurement of the alignment.


bcpowder84's measurements

Y = 44.6 mm
X = 43.2 mm Spec 41.1 +/- 1.8 mm Off-Trail 850s (38.1 +/- 1.8 mm for Trail 850s)
Y-X = 1.4 mm Spec 3.1 +/-0.93 mm 2.17 mm to 4.07 mm (All 850s)


If the clutch high spot happened to be near the secondary when bcpowder84 took the measurements, then turning the primary 180 deg would change the Y-X offset by 1.2 mm (2 x the 0.6mm runout). The X would decrease by 0.6mm and the Y would increase by 0.6mm leaving the Y-Z offset within spec at 2.6mm.


Possible measurements with primary turned 180 deg

Y = 45.2 mm
X = 42.6 mm Closer to spec 41.1 +/- 1.8 mm (Off-Trail 850s)
Y-X = 2.6 mm Closer to spec 2.17 mm to 4.07 mm (All 850s)


To get an accurate measurement for the alignment, I am assuming the primary needs to be positioned with the high and low spots perpendicular to the Center to Center line between both clutches.

The belt print should also reveal a great deal, and the manufactured offset could possibly make this process easier.


Below is a link to a good thread over on SnoWest. There are a several good threads on various forums, but the one I am posting on here is the only one I have seen where the owner shared pictures of taking the alignment. So it is worth linking the good ones.

https://www.snowest.com/forum/showthread.php?t=432883&page=4

 

[NeilV]

Sent from my iPad using Tapatalk