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RPM Issues

Solby

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Nov 26, 2007
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Colfax, WA
Anyone else have RPM issues when in deep powder pulling long hills. Day 1 at 7000 feet I was pulling 8300 RPM on short pulls. Day 2 did a long pull with snow on the hood, intake vents open seemed to only give my 8000 RPM. After we got to the top and rode around up there on shorter pulls I was back up to 8300 RPM. Stock 850, geared down, indy specialty clutching. Almost seems to me like pipe temp is derating my power at times....
 

RanOutofTalent

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Dec 20, 2014
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Mine does something very Similar all the time. I have lightened and balanced clutches is all.

2021 khaos 165 QD2 with the 2.75.

I hope someone could shed some light on this.
I have been diligent about keeping my track tighter than normal as it keep ratcheting every couple rides. At 650 miles for the season now


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A
Nov 26, 2007
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Elko, NV.
I've found that the 216 belt will perform this way when heated in long pulls, clutching efficiency goes in the toilet. I started running the Gates Carbon 45C4553 and the problem went away entirely. Take a look at your sheave faces the next time you feel this unexpected RPM loss, if you see a brown film on your sheave faces you've found your problem. A lot of folks have rave reviews of the 216, I ride 40-50 degree ambient air temps most every ride and have found in high ambient air temps the stock belt leaves a lot to be desired.
 

Solby

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Nov 26, 2007
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Colfax, WA
I've found that the 216 belt will perform this way when heated in long pulls, clutching efficiency goes in the toilet. I started running the Gates Carbon 45C4553 and the problem went away entirely. Take a look at your sheave faces the next time you feel this unexpected RPM loss, if you see a brown film on your sheave faces you've found your problem. A lot of folks have rave reviews of the 216, I ride 40-50 degree ambient air temps most every ride and have found in high ambient air temps the stock belt leaves a lot to be desired.
@AdrenalineAddict the 44C4553 is the belt for a pro-ride sheave angle. 45C4553 is for Axys. 47C4572 is the correct belt for an 850. I tried the 44C4553 not knowing that the sheave angle was different and I fought belt slip. You could see where the belt was not matching the angle correctly on the worn belt. Since going to the 47C4572 I haven't had any slipping.
 
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go-on-two

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Hey Solby i was under the impression that the 47C4572 was nearly identical to the 45C just a touch longer??
Are you sure it is a slightly different angle?
 
A
Nov 26, 2007
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I am curious about this because the gates site calls for the 45C4553 when you look up the belt for the Polaris 850. The belt angles are different for sure.
 

MKULTRA

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@AdrenalineAddict the 45C4553 is the belt for a pro-ride sheave angle. 47C4572 is the correct belt for an 850. I tried the 4553 not knowing that the sheave angle was different and I fought belt slip. You could see where the belt was not matching the angle correctly on the worn belt. Since going to the 47C4572 I haven't had any slipping.
the 553 is not for the pro ride.
it's the axys belt
 

d8grandpa

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Gates has a new R belt out to use instead of the C belt, that Tony says is working good.
 

d8grandpa

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I am currently running TRS clutching with the 47C and it is working awesome. No RPM fading, ran across a long lake at about 4500’ hit 8400, and 70mph. Holds 8250-8300 on long pulls all day long. At around 600 miles on current belt.
 

go-on-two

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I am also running Tony's clutching but with the 45C and having major issues with belt slipping only when in the deep powder. Its getting in somewhere, probably need to seal up around the headlight and cover some hood vents I guess. Always something!!!
 

Sheetmetalfab

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I am also running Tony's clutching but with the 45C and having major issues with belt slipping only when in the deep powder. Its getting in somewhere, probably need to seal up around the headlight and cover some hood vents I guess. Always something!!!

Footwell and under the primary clutch.

Both equally suspect.
 

BrapBirk

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Once your belt overheats it will no longer hold proper RPM. On a very long pull (over a min) in deep snow, you can watch the RPM start to drop off as the belt gets hotter and hotter. Stop, let the belt cool off, and the RPM will return. All part of the CVT clutch. A ski doo will do the same thing.
 

Sheetmetalfab

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Once your belt overheats it will no longer hold proper RPM. On a very long pull (over a min) in deep snow, you can watch the RPM start to drop off as the belt gets hotter and hotter. Stop, let the belt cool off, and the RPM will return. All part of the CVT clutch. A ski doo will do the same thing.
^^^^ and that’s how you know your clutches need help.......

If it acts like a skidoo especially.......
 
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Solby

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I am also running Tony's clutching but with the 45C and having major issues with belt slipping only when in the deep powder. Its getting in somewhere, probably need to seal up around the headlight and cover some hood vents I guess. Always something!!!
I sealed on the left side of my headlight vertically, that helped keep the snow off the top of my oil reservoir. Plastic on the lower parts of the footwell vents.
 

damx

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Also rvt the rubber strap for the side panel, and the aluminum tray thing that the oil bottle sits on. Both right in front of the primary and let snow in.
 

Murph

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With proper clutching and a belt with more grip than the 1216, you can experience a loss of rpm when the EGT sensors get really hot. The stock can (what I run) gets so hot under extended runs that it will melt all the paint off the bulkhead brace that it is mounted to.

You will also notice a drop in rpm after a stuck or break until the EGT sensors return to normal operating temp.

I’ve been running the new Gates 47R (Redline) belt with TRS clutching. I did have to add a shim under my spider that was originally setup for a 47C. The Redline measures the same but must bulge out to the sides slightly when wrapping around the bottom of the primary shaft.
 
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