2017 RMK 8300rmp down to 7700rmp with elevation. Why?

604_MTX · Apr 10, 2018

Hey guys,
I have a 2017 Axys Pro 155x26" with Diamond S titanium can.
When I unload the sled at 3000ft I get full 8250-8300 RMP's going up the trail.
But as soon as I get to 5000ft and above I can't seem to get past 7800, 7900 max.
Sled has 1400 miles.

Here what I tried so far:
1) Replaced the relays (thinking its an electrical issue)
2) Adjusted belt tension
Where should I look next? Any tips? Ideas?

Thanks!

IMG_7085 by xzibituz, on Flickr

Scott · Apr 10, 2018

Motor mounts.

BTW, great photo!

aksledjunkie · Apr 10, 2018

Is this new? Cause if it isn't new and the sled does this every time I'd say everything is running perfectly and you are just running too much clutch weight for that high of elevation.

BILTIT · Apr 10, 2018

As said above, did you change clutch weights? You need to for elevation changes, see the owners manual.

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604_MTX · Apr 10, 2018

aksledjunkie said:
Is this new? Cause if it isn't new and the sled does this every time I'd say everything is running perfectly and you are just running too much clutch weight for that high of elevation.

I bought the sled used with 700 miles on it. I put another 500 miles now and just noticed the RPM change last 4-5 rides. before than it was too deep to read the display once I was off trail. Dealer doesn't know if the old owner changed weights or not.... What would the weights be for 6000-8000 ft? And what about the spring? Could a spring cause this?

dboe03 · Apr 10, 2018

10-64's and the spring is 120/320 according to the manual. Mine is 2016 but don't think they changed anything.

AdrenalineAddict · Apr 10, 2018

Provided clutching is stock go with 10-62's. My '17 gets real rich above 40 deg. and can be almost impossible to tune to 8,100 in the spring. I ride higher than you but at 7,500' down the trail I will see 8,350 rpm, at 10,000' I will only see 7,900 r's. 10-60's will get me back to 8,000, this pretty much follows Polaris manual recommendations. I picked up an '18 a couple months ago and it seems to be mapped a bit leaner pulling 8,350 down the trail with 10-64's and 8,150 at 10,000'. Overall it runs much stronger than my '17 ever did.

Big10inch · Apr 11, 2018

I would check compression. 1400 miles is getting up there for a Polaris motor. I don't know of any without turbos that haven't lost power by that mileage. Also mentioned, motor mounts, primary clutch rebuild time as well... Good Luck

RMK935VA · Apr 11, 2018

As mentioned, your clutch weights would be my first consideration. I had a 16 with a Diamond S van and it was happy at around 8150 with 62 gram weights. I added an SLP pipe and went up to Belly Buster 64 gram weights or maybe it was 64 to 66 but I don’t think so. Anyway, with the pipe and 2 gram heavier weights, I was seeing 8300 consistently. Also, is your helix stock? I was using a Carl’s multiple angle helix in the less steep ramp. It revved faster and held a higher rpm in that ramp.

Wheel House Motorsports · Apr 11, 2018

Check clutch bushings next to rollers. I have been having some regular issues with sled performing under load and its generally those being worn out if not completely melted out of the clutch along with weight bushings etc. causes the sled to fail to pull RPM under load. Also, even if the belt isn't pulling threads I notice mine just do not pull the same after 200 hard miles on them. they aren't worn out by any means, they just dont work right.

10-64's should be screaming at 5k feet.

Ive had a 16/17/18 axys 155 2.6 and all of them will pull 64's over 8000 RPM up to around 10k feet when the sled is in proper condition. At 5k it pulls easily 82-8300 in deep snow.

Ktmsx350f · Apr 11, 2018

Big10inch said:
I would check compression. 1400 miles is getting up there for a Polaris motor. I don't know of any without turbos that haven't lost power by that mileage. Also mentioned, motor mounts, primary clutch rebuild time as well... Good Luck

Not for an Axys 1400 is nothing. I have 3500 with turbo on stock motors no issues compression is good. Pro ride for sure. Axys pistons are much better

Ktmsx350f · Apr 11, 2018

What exhaust is on it? We have seen 7 sleds now this winter with GGB, Mbrp and one other ****ty can that developed a RPM loss over time. All were fixed with a stock or better after can. Check motor mounts even if they are new if they move to much they will cause issues. Some will wear aluminum around the mount so new mounts aren’t tight. Set belt deflection tight Polaris spec is way to loose. Track in the air with track tension set make the belt tight as you can that it doesn’t spin the track but you can grab a lug or the secondary and make it spin easy. Check clutches for wear bushing pins rollers ect. A torque stop on the mag side helps too.

Big10inch · Apr 12, 2018

Ktmsx350f said:
Not for an Axys 1400 is nothing. I have 3500 with turbo on stock motors no issues compression is good. Pro ride for sure. Axys pistons are much better

Well my Axys blew the motor well before 1400 miles. It also needed a primary clutch rebuild, motor mounts and a power valve cable. You share your experience, I will share mine...

I think the motor is toast by 1400 miles. If you look around, I am not alone with an Axys motor failure.

XFIRE800 · Apr 12, 2018

Big10inch said:
I would check compression. 1400 miles is getting up there for a Polaris motor. I don't know of any without turbos that haven't lost power by that mileage. Also mentioned, motor mounts, primary clutch rebuild time as well... Good Luck

Big10inch said:
Well my Axys blew the motor well before 1400 miles. It also needed a primary clutch rebuild, motor mounts and a power valve cable. You share your experience, I will share mine...

I think the motor is toast by 1400 miles. If you look around, I am not alone with an Axys motor failure.

You can find the same results from any mfg. My Axys runs better now at 1300 miles than it did at 500. The guys i know that have had them apart have seen ZERO issues with similar miles. Not doubting that you have had problems, but the sheer number of axys’ on the snow will considerable miles and no engine issues shows that this is the best engine polaris has had in years. Some people could break an anvil, just saying.

TRS · Apr 12, 2018

XFIRE800 said:
You can find the same results from any mfg. My Axys runs better now at 1300 miles than it did at 500. The guys i know that have had them apart have seen ZERO issues with similar miles. Not doubting that you have had problems, but the sheer number of axys’ on the snow will considerable miles and no engine issues shows that this is the best engine polaris has had in years. Some people could break an anvil, just saying.

I must be the guy with a rubber hammer and an anvil. Engine number 4 going in for 2018.

revrider07 · Apr 12, 2018

Trs do you care to share the issues that these motors had when they failed? 4 seems to be a lot.

Wheel House Motorsports · Apr 12, 2018

Haha, Generally they are holding up well, Tony seems to have a knack for wearing things out fast..

I would check clutch stuff, those get so worn out so fast, I think a lot of guys just dont notice the slow power fade. Ive gotten 1 new primary and 1 rebuilt under warranty now at 1600 miles on my 18 axys.

AdrenalineAddict · Apr 12, 2018

My '17 Axys grenaded at 2,300 miles, so I decided the Axys is a better motor than the pro of which I grenaded 4 of them around 1,900 miles each between 2012 and 2015.
Thank god for warranty or I would have been forced to find a cheaper hobby.

Big10inch · Apr 12, 2018

XFIRE800 said:
You can find the same results from any mfg.

Actually, it is MUCH more difficult to find these issues in the other brands. I watch Doo guys rack up trouble free miles year in and year out. I am having to ride 8-10 yr old back up Cats that run harder than any of my last three Poo's did, and never seem to give me any trouble even when I ride the snot out of them.

It wasn't just one sled that led me to this opinion but, the Polaris takes a LOT more work, time, money and warranty work to be top notch on the snow. I hope like everything that the 850 proves to be a good motor because I LOVE the chassis. You will never convince me that the 800 Axys motor is good enough, and it certainly isn't up to par with the Cat or Doo for power or reliability. That is just not a contest if you are being truly honest about the three.

XFIRE800 · Apr 12, 2018

Big10inch said:
Actually, it is MUCH more difficult to find these issues in the other brands. I watch Doo guys rack up trouble free miles year in and year out. I am having to ride 8-10 yr old back up Cats that run harder than any of my last three Poo's did, and never seem to give me any trouble even when I ride the snot out of them.

It wasn't just one sled that led me to this opinion but, the Polaris takes a LOT more work, time, money and warranty work to be top notch on the snow. I hope like everything that the 850 proves to be a good motor because I LOVE the chassis. You will never convince me that the 800 Axys motor is good enough, and it certainly isn't up to par with the Cat or Doo for power or reliability. That is just not a contest if you are being truly honest about the three.

8-10 year old backup cats that run harder.... If you want to blow smoke go have a cigarette. That 07-09 cat 800 motor was a dog. Which cat? Ive had first hand experience blowing up plenty of 10-17 suzuki 800s that are “bulletproof” (deep down im a cat guy and have ridden cats most of my life). I get sick of all the whining about the 800 in the axys. The engine is fine, its the electrical components that are junk. There are more axys 800s than doos or cats so simple math tells you there will be more failures. As hard as ive tried to believe that this motor, heck even the 800 from the pro, is a p.o.s., real world experience has shown me otherwise. 100’s of pros and axys that i have ridden with or friends have ridden with and can’t think of a single one towed out for engine reasons. Forums have their place, but most issues get blown out of proportion.

2017 RMK 8300rmp down to 7700rmp with elevation. Why?

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