[ExcursionPSD]

Not quite. It only produces the lowest CVT ratio at launch. At low track speed, the CVT adjusts to the same ratio as it would with a looser belt deflection.

Thank You, Sir.
Absolutely right. Think about it. As soon as the secondary starts to open up, to upshift, the tip of that deflection set screw is contacting nothing but AIR.

It can have NO EFFECT on how the clutch action works until the engine goes below engagement rpm, and the secondary closes enough to hit the tip of the deflection set screw.

In ANY kind of a rolling start race... NO EFFECT.

The wrong width or length or cut angle of a drive belt ABSOLUTELY will affect performance somewhat thru the range of clutch action.

The belt deflection adjustment can help reduce that effect, AT LAUNCH and also before engagement rpm. ONLY.

 

[Lid2]

It also stops the sled from starting off in to “high “ of gear so to speak. Where the belt is lower in secondary and higher in primary before you get any action. Not unlike other sleds and brands I personally know of 850s that are not damaged but make notably less power on a dyno than others. Many 850s that are lazy is becuse for some reason they are more suseptable to the ecu summing the sled down. Higher water temp can cause this but it’s not the only factor. Many sleds lose rpm and you can hear them running in a crappy state of tune. Only to switch back in an instant to a crispy animal without what I would call a necessity. For some reason some sleds this calabration issue is more prevelant. I will also add the masses of riders are not in tune with thier machine enough to hear it and observe it in rpm and performance. I’ve had this discussion with guys who said oh no mine doesn’t do it at all . I get on it and withing a handful of miles the sled is derating. They just are ignorant to it. Btw before we go down the rabbit hole. This is NOT a cvt issue. It’s in the ecu.

 

[ExcursionPSD]

LId2,

Yes, the proper deflection setting assures, you start out in as low a 1st gear as is possible. If you have an overlong / narrow belt, you will actually get a lower starting ratio, for a moment, but your ratios and shifting from that point on are still affected by the out of spec. drive belt.

One of my Request items for the software upgrades to the 7SDD, is for display and logging of sled operation and performance data, that is available thru the CAN communications network on the sled. In addition to the items already shown.... RPM, MPH, coolant temp, Voltage (actually 3 different circuits + battery) there are a lot of metrics I would like to see and put into a log file, that could be massaged/displayed/compared by an Excel spreadsheet:

Throttle Position, E-VES II valve position (Hi, Med, Low), Ignition Timing, Fuel delivery, Intake Air Temp. and Barometric Pressure, Some indication of DET status, Pipe & Resonator EGT temps, Fuel pressure & Fuel Temp.

 

[Sledtuner360]

LId2,

Yes, the proper deflection setting assures, you start out in as low a 1st gear as is possible. If you have an overlong / narrow belt, you will actually get a lower starting ratio, for a moment, but your ratios and shifting from that point on are still affected by the out of spec. drive belt.

One of my Request items for the software upgrades to the 7SDD, is for display and logging of sled operation and performance data, that is available thru the CAN communications network on the sled. In addition to the items already shown.... RPM, MPH, coolant temp, Voltage (actually 3 different circuits + battery) there are a lot of metrics I would like to see and put into a log file, that could be massaged/displayed/compared by an Excel spreadsheet:

Throttle Position, E-VES II valve position (Hi, Med, Low), Ignition Timing, Fuel delivery, Intake Air Temp. and Barometric Pressure, Some indication of DET status, Pipe & Resonator EGT temps, Fuel pressure & Fuel Temp.

That would be handy when you beat your buddy and he says ahh mine went into derate! Or when your buddy beats you you can show that your sled did.

 

[racerdave]

LId2,

Yes, the proper deflection setting assures, you start out in as low a 1st gear as is possible. If you have an overlong / narrow belt, you will actually get a lower starting ratio, for a moment, but your ratios and shifting from that point on are still affected by the out of spec. drive belt.

One of my Request items for the software upgrades to the 7SDD, is for display and logging of sled operation and performance data, that is available thru the CAN communications network on the sled. In addition to the items already shown.... RPM, MPH, coolant temp, Voltage (actually 3 different circuits + battery) there are a lot of metrics I would like to see and put into a log file, that could be massaged/displayed/compared by an Excel spreadsheet:

Throttle Position, E-VES II valve position (Hi, Med, Low), Ignition Timing, Fuel delivery, Intake Air Temp. and Barometric Pressure, Some indication of DET status, Pipe & Resonator EGT temps, Fuel pressure & Fuel Temp.

Are you saying this fancy new gauge doesn't have max recall of rpm and/or mph?

 

[geez150]

That's correct.

 

[orville-x]

LId2,

Yes, the proper deflection setting assures, you start out in as low a 1st gear as is possible. If you have an overlong / narrow belt, you will actually get a lower starting ratio, for a moment, but your ratios and shifting from that point on are still affected by the out of spec. drive belt.

One of my Request items for the software upgrades to the 7SDD, is for display and logging of sled operation and performance data, that is available thru the CAN communications network on the sled. In addition to the items already shown.... RPM, MPH, coolant temp, Voltage (actually 3 different circuits + battery) there are a lot of metrics I would like to see and put into a log file, that could be massaged/displayed/compared by an Excel spreadsheet:

Throttle Position, E-VES II valve position (Hi, Med, Low), Ignition Timing, Fuel delivery, Intake Air Temp. and Barometric Pressure, Some indication of DET status, Pipe & Resonator EGT temps, Fuel pressure & Fuel Temp.

That would be a fantastic idea. The discussion of this topic has come up a number of times over the years. One would think it could be VERY helpful for dealers and Polaris themselves to help troubleshoot sled issues. The information is there, just inaccessible except for someone with access to digital wrench. I have a couple data traces from my '15 800 when I was having relay issues and trying to figure out if it was the ECM inputs and outputs or if it was something else. Lots of cool info locked up in there....

 

[Lid2]

That would be great. At least then you could say this is what is happening when this derating occurs in real time. Then find out why it’s doing it and formulate a fix. What I do know. 1- it’s not from the can sensor . 2- observed water temp is not the cause (although it does have effect on tuning it’s not the cause of this issue. As the issue will occurs with Low observed water temps. ) 3- I don’t believe it’s preignition as I have blended 110 leaded race fuel with a weight very close to pump fuel with 91non eth to a blended octane as low as 93 and up to 100. And condition still exists and is not bandaided with octane. 4- pipe temp seems to be a correlation. Unlike the 800s which get faster and climb in rpm with heat. The 850 sleds in general and ones effected by this deration(for lack of better term ) get slower the more you run them and rpm goes away . You can hear the sleds get lazier and lazier it’s getting richer and richer. Timing may or may not be getting pulled also. And I’m. It sure about valve position but they def. get super rich. Park sled for an hour get back on and it runs as it should until it starts the process again. It will also change state of tune without warning or tangible reason as you ride. I can hear them become happy again without even looking at tach. Go wot. And yup sure as shit the rpm is back and sleds flying until it’s changes it’s mind again. Polaris needs to address this at factory level. And offer a “fix “ for this. There is no way they haven’t heard or seen this before. No way possible. If they were to tell me they have no idea what I’m taking about I’d probably have a heart attack from a bullshit overdose .It’s not just a sled here or there I believe It’s common. . Wether an owner is savvy enough to catch it or not I can’t answer that. Also for note and admittedly without documented fact some sled owners who are onto this say thier sleds did not do this in break in mode. Obviously since they are out of break in mode I can’t ride it and verify. Any correlation to this claim. And I’m not sure if one was out back into break in with digital wrench if that’s literally exactly the same break in as a new out of crate sled . So yes I agree with excursion an on board data logger encompassing all the things he listed would be a big deal.

 

[ExcursionPSD]

Lid2,
I appreciate what you posted. Just to make it clear to others, the previous post is based on experience with the MY19-20 850 Patriot motor. We do not know if the 650 Patriot is going to have any of this behavior or not.

 

[ivar]

How can there be that much variance from one 850 to another?

looks like the 850 ECU operates within a narrow set of parameters, safeguards and conflicting demands... EPA regs + not melting side panels etc - or pistons
Like Lid says , the transition from happy / not happy is very noticable.

This kinda reminds me of the rpm fade on the first year 800HO..?

The 650 sounds like it runs much more consistent over a wider range of conditions without needing to go from "braap" mode to "bwaa" all the time

 

[geez150]

Seems like this heat soaked rpm/performance fade is something all the bigger sleds have. Same problems exist with the ZR9K/Sidewinders and if I'm not mistaken the 850 etec as well. I believe it's an industry "problem" to protect these sleds from EPA standards.

 

[Mavrick1]

looks like the 850 ECU operates within a narrow set of parameters, safeguards and conflicting demands... EPA regs + not melting side panels etc - or pistons
Like Lid says , the transition from happy / not happy is very noticable.

This kinda reminds me of the rpm fade on the first year 800HO..?

The 650 sounds like it runs much more consistent over a wider range of conditions without needing to go from "braap" mode to "bwaa" all the time

Well thank God my 2021 850 has not shown any of these issues yet, every time i hit the gas i get the exact same response, it flat out rips. Same RPM of 8250-8300 ever time, if something changes i will be sure to report about it.

 

[mxsnow]

When I sold sleds I set the belt,track and skis for MY customers,the manager saw me doing that and asked why,I told him and the next day we had a meeting with the service dept. Most dealers today use kids or a staff at the warehouse for setup.

 

[Hermit Rob]

When I first took out my VR1 650 137 it felt ok then at about 20 miles it felt like a lazy 600. Brought sled into the shop checked and adjusted belt deflection and took it back out. Felt very strong after adjustment. I now have 400 miles on and the sled and through the trails feels as strong as my 2016 800 Rush. Much more fun in the trails than my 2020 850 xcr 129. Anyone who has a new sled MUST check adjust belt deflection to achieve optimum performance. All around I feel the sled is probably the funnest and most complient sled I have ever ridden. Shocks valving is pretty darn nice.

I’m all over a 146 in March! Sat on a 146 at the dealer, and wow the more narrow chassis is wicked cool! All I could do to not trade my 18’ Assault 800 and walk out with it! Hoping the add Lime Squeeze to the color options in March 🤙 Gonna be a looooong summer 🤯😂

 

[sledlover]

I had several 600 Ski-Doo Etecs before my current Pro S 800HO.

All the Etec 600s suffered from RPM fade like what is being talked about on the Polaris 850. I tried various things to fix and never did. Alway ran premium.

This was part of the reason I switched brands. Bad enough riding a 600 then when it will only pull 7500 rpms its a real dog.

 

[Mudgunner]

looks like the 850 ECU operates within a narrow set of parameters, safeguards and conflicting demands... EPA regs + not melting side panels etc - or pistons
Like Lid says , the transition from happy / not happy is very noticable.

This kinda reminds me of the rpm fade on the first year 800HO..?

The 650 sounds like it runs much more consistent over a wider range of conditions without needing to go from "braap" mode to "bwaa" all the time

I pulled the sensor from the exhaust on my 2019 850 and it never had any fade. I’ll be doing it to my VR1 after it’s out of breakin mode.

 

[scuba1221]

I pulled the sensor from the exhaust on my 2019 850 and it never had any fade. I’ll be doing it to my VR1 after it’s out of breakin mode.

Pipe sensor or muffler?

 

[Lid2]

Yes

Lid2,
I appreciate what you posted. Just to make it clear to others, the previous post is based on experience with the MY19-20 850 Patriot motor. We do not know if the 650 Patriot is going to have any of this behavior or not.

yes 100 percent correct.

 

[Lid2]

sorry Guys I don’t want to derail the thread if anybody wants to continue lest do it in diffenet area. I’ll end with removel of the can temp sensor on trail sleds doesn’t resolve the derating. It’s in the ecu parameters being set wayyyyyy to safe or in conflict imo. Every here and there there is one that doesn’t do it much. I hope they addressed this for 21 going forward it’s super frustrating . If we ever get snow.i plan on riding 3-4 850 matrix and I will know if it’s better or not.

 

[rynex]

This hot pipe hp loss on the 840 is well documented over on dynotech. Jim has multiple write ups along with data showing that the 840 loses hp when pipe temp climbs. It’s really worth the $30 annual charge, there are mountains of useful information on Jim’s site. One of his more recent articles compares the stock 21 840 tune to BCM performances latest 840 tune.
As usual the stock tune loses hp on the second dyno pull when pipe temps climbs, but the BCM tune not only makes more hp on the first pull ( cold pipe ) and makes considerable more hp on the second pull with a (hot pipe) and at a higher rpm. As Lid has mentioned a lot of people won’t notice this drop in performance but some will, I always noticed it after long high midrange cruises my 19 840 would just run flat no matter if I held it wide open, if I was to slow down for a while and nail the throttle it would run like crazy something I noticed often while riding in Quebec.