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RPM Issues
- Thread starter Solby
- Start date
The gates site does recommend the 45C4553 for the 850 (hope this is right), I have noticed that my latest belt required a ridiculous amount of break in ride time before the belt contact area wears in and the sheave angle is matched (like 50-60 miles). when the angles aren't matched you will have a tuning nightmare. I almost sent my last belt back because the cut angle was so far off, but after a few 20 mile break in runs everything made contact and normal operating RPM were restored (kind of a hassle). I wish the 216 could handle the heat, they're an awesome belt in a normal low temp. environment. I went on a ride in the Rubies yesterday, when I left the truck my thermometer read 46 degrees, as I climbed the mountain I had to shed some clothes and I'm sure the air temp was +50, the C belt performed perfectly, no slip and no rubber compounds at all on the sheaves at the end of my ride, clean as a pin, pulled 8,000 to 8,100 R's consistently at 9,000' to 10,000'. I sure do enjoy the ride more when I can just ride instead of cooling, cleaning and trying to figure out why I'm having RPM issues.
2021 khaos with 500 miles. Snow is firm so I thought I would break in a new belt,Polaris 216. Right away noticed it was not working right lower Rpms And shifting off. Felt like it was in high gear when it should’ve been low gear.
figured I’d try to break it in. after two days of riding still not working. Came across the lake on the way home at 6500 RPMs. Hit the gas could only get 7400 or less. Stopped hit the gas got 8300 then went went back down to 7800. I’m going to go back and try the original belt today and maybe some other belts have laying around. I haven’t ran a Polaris Belt in years. I have been running gates 45C on all my sleds. I’m not a happy camper at this point.
figured I’d try to break it in. after two days of riding still not working. Came across the lake on the way home at 6500 RPMs. Hit the gas could only get 7400 or less. Stopped hit the gas got 8300 then went went back down to 7800. I’m going to go back and try the original belt today and maybe some other belts have laying around. I haven’t ran a Polaris Belt in years. I have been running gates 45C on all my sleds. I’m not a happy camper at this point.
Any of you running the Gates 47C4572 have to shim your primary to compensate for the extra width of the belt? I have '21 Khaos 850. Thanks
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So, I dug out the belt/sheave gauges to check belt angles on multiple belts.
OEM and Non-OEM. Belt angles were anywhere from 26* to 30* on any given belt. I also measured belt widths with my 28* caliper, they are not close to their advertised spec. Now you can see were proper breakin is mandatory. Letting the belt to sheave angle get a match.
You don’t want to go down the road of the perceived sheave angles. You would be amazed.
OEM and Non-OEM. Belt angles were anywhere from 26* to 30* on any given belt. I also measured belt widths with my 28* caliper, they are not close to their advertised spec. Now you can see were proper breakin is mandatory. Letting the belt to sheave angle get a match.
You don’t want to go down the road of the perceived sheave angles. You would be amazed.
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I went to Polaris today. They’re saying nothing wrong with my driven clutch. They’re saying it has other problems. Needs to go on the digital wrench. My dealer can’t do that for two weeks. Probably a 15 minute job. I’ll be looking for a new dealer to snow check next year.
I've been having lots of RPM issues on my sled this winter (amongst other issues) and I believe my dealer figured out this issue finally.
This is a 2021 850 khaos 155 with the "low elevation clutching" . Would only pull 7200 on groomed trail with 3 inches of powder on top. Let off and get on it and the rpms would go to 7400, then slowly climb to 8, maybe. Seemed to actually pull better when loaded, like climbing a hill. My dad has the same sled in a 165 and I jumped on that thing back to back and it would pull right to 8150 and stay there. Both are stock.
We ended up going back to the 42 straight cut helix and SLP blue/pink spring. Huge improvement on my sled. Might try a different secondary spring for more backshift.
This is a 2021 850 khaos 155 with the "low elevation clutching" . Would only pull 7200 on groomed trail with 3 inches of powder on top. Let off and get on it and the rpms would go to 7400, then slowly climb to 8, maybe. Seemed to actually pull better when loaded, like climbing a hill. My dad has the same sled in a 165 and I jumped on that thing back to back and it would pull right to 8150 and stay there. Both are stock.
We ended up going back to the 42 straight cut helix and SLP blue/pink spring. Huge improvement on my sled. Might try a different secondary spring for more backshift.
That partly answers a question I'd been asking about side angles. It didn't sound right to me that so many people were running (and Gates spec'd) belts with a nominal 28º side angle in sleds that called for a 26º belt (Pro chassis). I'm still not sure what all is at play, but it sounds like the 28º vs 26º spec doesn't matter with any belt that will fit newer machines (that may go all the way back to EDGE sleds, when the 11.5" center distance came in). I had some concern about running a "28º" belt, but after 200 miles or so of mixed riding, I'm finding the wear marks on the belts really don't extend any higher than the bottom cogs. So despite the spec for the belt I'm running (47C4572) being steeper than the quoted side angle of the OE belt (3211115), the clutch is engaging with the inner part of the belt first, just like it should.
What elevation are you riding at?
Usually 1000-2000'
Guys service after the sale is everything. I bought my Khaos from another dealer because my dealer was sold out this year. That dealer said two weeks to put my sled on the computer. That’s just unacceptable. My old dealer took care of me in one day. I was losing RPMs big time . He did the new map update. Also check exhaust pressure regulator. Re-learn the power valves. Which he says he doesn’t need to do hardly ever on the 850s. The new map is not a recall just a service bulletin if you’re having problems. I just took my sled for a short rip and it’s ripping. I’m a happy camper tonight.
