Belt issues on the 850

[Jake jenkins]

I heard brp stopped production of all 850 summits this true ????


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[snopro]

I heard brp stopped production of all 850 summits this true ????


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Yep they are all built now.

 

[assaultn]

I noticed this as well. Also noticed the very minimal amount of engine brake. hmmmm

After I blew my belt it left a giant mess on my clutches . I rode home on my spare belt and when I got there I could see only half the primary was scrubbed clean.

 

[Caper11]

I've been looking and comparing stock clutch setups over the past few years between the 850 and the Etec to try and get a handle on how the Pdrive is coming setup compared to a TRA. I know it's challenging without really knowing the ramp profiles of each, but there are a lot of similarities. What is really jumping out at me in the spreadsheet I've made is the secondary spring. Helixes are the same, primary spring are of similar forces, gearing at 1:1 on a 154 is very similar... leading me to believe the ramps in the TRA and Pdrive are acting fairly similarily. What is quite different is the secondary spring. The spring used in the G4 is a Blue 157/221 whereas the spring used in last years Etec was a Black 157/303 no matter on track length or depth. Based simply on that it would almost appear the secondary is shifting too soon putting the machine into a higher gear quicker than previous years. This could easily explain why the belt is heating. I would be real curious to see what a change to simply the Black secondary spring would do.

Where are you finding the black sec spring that came on a 800etec??

The 800etec came with a blue/blue. My 13 xm did and my 16 t3 did as well, and I wouldn't run that spring and helix on my 800etecs.

Yes aside from the sec spring, you are correct in your findings and I took notice of that when I saw the clutching
specs on the prototypes.

If I owned a G4 I would recommend a black spring or a purple/purple, and a gear down as a simple fix until a clutch kit maker comes up with a kit.



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[Rotax_Kid]

Where are you finding the black sec spring that came on a 800etec??

The 800etec came with a blue/blue. My 13 xm did and my 16 t3 did as well, and I wouldn't run that spring and helix on my 800etecs.

Yes aside from the sec spring, you are correct in your findings and I took notice of that when I saw the clutching
specs on the prototypes.

If I owned a G4 I would recommend a black spring or a purple/purple, and a gear down as a simple fix until a clutch kit maker comes up with a kit.



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Hi Alt specs from 16...lists drivetrain setups for all elevations.

 

[Utter_Kaos]

Any one hear of a clutch kit out yet for the 850


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[Rotax_Kid]

Where are you finding the black sec spring that came on a 800etec??

The 800etec came with a blue/blue. My 13 xm did and my 16 t3 did as well, and I wouldn't run that spring and helix on my 800etecs.

Yes aside from the sec spring, you are correct in your findings and I took notice of that when I saw the clutching
specs on the prototypes.

If I owned a G4 I would recommend a black spring or a purple/purple, and a gear down as a simple fix until a clutch kit maker comes up with a kit.



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The purple would be worth a shot but gut feeling says it would delay the shift a little too much. I have no miles on my machine yet. We have a bit of snow but its -30 this am. I have a black to try or a green could be a good option here. Could be wrong and until we get on the snow its all an educated guess

 

[Evils33d]

I went to clickers #1 today and the sled still overrevs.. up to 8200 , down from 8500. and watch out for the pipe sensor, it comes out and then burns a hole in the airbox.

 

[Merc63]

What elevation and snow?

 

[Caper11]

Hi Alt specs from 16...lists drivetrain setups for all elevations.

Nice link. Yah must of been looking at the 800r charts, they show a black sec spring and the etec is blue.

The pur/pur was the sec spring of choice for doo up until 2012 when they went to the 40deg helix.


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[Rotax_Kid]

Nice link. Yah must of been looking at the 800r charts, they show a black sec spring and the etec is blue.

The pur/pur was the sec spring of choice for doo up until 2012 when they went to the 40deg helix.


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Yeah its a pretty handy reference and alot of people dont even know these exist. Hoping to start testing low altitude next week. Going to swap out for a black secondary and have a set of 35mm goodwin pins here. Quick calcs show this won't be enough so need to order a 38mm set tomorrow unless I can put the 35mm weights on the OEM 38mm pin. Also have full low altitude setup to tinker with. Most years I can test in the quarter across the road from me...but this year need to go South for snow.

 

[BRP QSC]

So then for all you guys with belt issues on the 850's BRP hasn't come up with anything yet? well besides a replacement belt. the pic of the clutch a few posts ago has had the belt to the top of the sheath but man that belt got real hot to leave crap like that.
Sure am glad i kept my XM for another year

 

[ZIG]

I noticed some belt material after i just rode it for only 1 mile. I wonder if this is part of the break in on the belt?

 

[d8grandpa]

I've been looking and comparing stock clutch setups over the past few years between the 850 and the Etec to try and get a handle on how the Pdrive is coming setup compared to a TRA. I know it's challenging without really knowing the ramp profiles of each, but there are a lot of similarities. What is really jumping out at me in the spreadsheet I've made is the secondary spring. Helixes are the same, primary spring are of similar forces, gearing at 1:1 on a 154 is very similar... leading me to believe the ramps in the TRA and Pdrive are acting fairly similarily. What is quite different is the secondary spring. The spring used in the G4 is a Blue 157/221 whereas the spring used in last years Etec was a Black 157/303 no matter on track length or depth. Based simply on that it would almost appear the secondary is shifting too soon putting the machine into a higher gear quicker than previous years. This could easily explain why the belt is heating. I would be real curious to see what a change to simply the Black secondary spring would do.

You are on the right track with your assessment, i have a buddy with an 850 and he has changed out his secondary to the black spring and is getting much cooler clutches. He still thinks he needs to add more weight to the primary as it is still over revving you you hammer on it, hits 82-83ish before settling back down to 8.
He thinks they have them setup for way to high of elevation were the engine would be making less power, but most are riding in the 5-7 range and engine is putting out way to much torque for stock clutching.

 

[Islanddoo]

Rode two solid days in 3' of powder with Black secondary spring at 4 to 5K in altitude, you could touch the clutches after riding for 10 mins! Zero belt dust! Just need to add some weight to primary as it would flare to 8200 then settle around 7900 in clicker 1. I would suggest the black spring to anyone riding an 850 this year.

 

[SidewaysInto3rd]

Rode two solid days in 3' of powder with Black secondary spring at 4 to 5K in altitude, you could touch the clutches after riding for 10 mins! Zero belt dust! Just need to add some weight to primary as it would flare to 8200 then settle around 7900 in clicker 1. I would suggest the black spring to anyone riding an 850 this year.

just ordered the black spring and a weight kit ... hopefully this is the answer !

do you get any better engine braking with the spring ?

 

[crazy_cappa]

I'm surprised dynamo Joe, or rooster built aren't all over this. Sounds like there is a huge market and gains to be had by clutch kits again. Edit- just checked dynamo's site looks like he is working on it but won't be available for quite some time yet

 

[RGM]

I was guiding 4 guys on 850 a couple of days ago. All there belts were way to loose. When you push on the belt between the clutches you only want to have 1"of play in it.

 

[Caper11]

I'm surprised dynamo Joe, or rooster built aren't all over this. Sounds like there is a huge market and gains to be had by clutch kits again. Edit- just checked dynamo's site looks like he is working on it but won't be available for quite some time yet

Stay tuned. It takes time to develop a kit.


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[Bernoff]

Are the sleds that blow belts taking out the pto seal too or are the seals different than a 2013. I never seem to be lucky enough to not have to replace seal right away too.