AXYS Down on 1500RPM

die hard poo · Jan 12, 2016

So my sled was running perfect for the last 500 miles. It would pull 8500rpm consistently. Only mods are SLP Pipe/can, and SLP Clutching. My previous ride it ran perfect, then while I was doing my post ride inspection, I noticed the SLP pipe was cracked around the probe bung. Luckily my dealer had a SLP pipe in stock so I replaced it with a brand new SLP pipe. This is the only change to the sled from then to the next ride.

Then yesterday I went on a ride to the exact same place. This time I noticed on the trail up the sled was feeling kinda weird, not as snappy but I wasn't really getting on it since it was just the trail. Then when I got to the mountains I went to get on it and instantly noticed it was only pulling 7000-7300rpm consistently. It wasn't throwing any engine codes or det lights.

So naturally I went for the easy troubleshooting things on the mountain:
Replaced the spark plugs- No change, the old ones look good, running chocolate brown on the tip.
Replaced the clutch belt-No Change
Swapped secondary clutch with my Pro that was with me- Ran worse(steeper helix than stock), so swapped back.
Swapped to Ethanol mode from 91 premium- Ran worse which I expected
Replaced Primary spring-No change

Ended up saying screw it and rode it as is the rest of the day like it was since the snow was great(60 miles). It would idle fine, and it never hiccuped or sputtered, just wasn't making power and pulling RPM and seemed not have have the mid range snap.

So today in the garage,
-I looked over ever electrical connection and wire for a rub, nothing. Figured there wouldn't be otherwise I would most likely get an engine code.
-Replaced the exhaust pipe/can with the stock one- On the stand at WOT it would only pull 7850rpm. Obviously no load on the motor, but it should still pull peak RPM of ~8500rpm. I also changed the clutch weights back to what I had with the stock exhaust.
-Checked compression-Both cylinder reading exactly the same, 118 psig.

Unfortunately I am at a loss. The only thing I can think of is the exhaust valve actuator isn't opening the valves all the way. But there are no codes either... And my dealer doesn't have time to look at it for another two weeks and I don't have time to wait that long.

So do you guys have any input? I can't really test the sled other than on the stand because we have no snow at the house.

I open to suggestions!
Thanks in advance

icr · Jan 12, 2016

Sounds like exhaust valve to me. Have you checked the valves/all hoses for sludge?

AKDoug · Jan 12, 2016

118 PSI at Kenai altitude? That sure seems low. Gauges are notorious for being wrong, though.

die hard poo · Jan 12, 2016

Ya my gauge always reads low, but the main thing is they're both the same psi.

And I watched the actuator move while the modulating the throttle. When the sled is off it is in the middle position. Then when the sled starts, the actuator pulls the cable to the top. Then with about mid throttle, the actuator goes back to the middle position, finally near WOT, the actuator goes all the way down opening the valves fully. The actuator seems to move freely when the sled is off. I will take exhaust valves apart to see anything obvious.

die hard poo · Jan 12, 2016

icr said:
Sounds like exhaust valve to me. Have you checked the valves/all hoses for sludge?

This has a cable operated system, but I plan on taking the valves apart to inspect.

Perk · Jan 12, 2016

From the story (if I followed it correctly) it sounds like the replacement pipe your dealer gave you could be the issue - you rode 500 miles and sled ran awesome - you then found a crack around the sensor bung in your pipe and replaced it - after replacing the pipe, it runs like crap - then you mentioned that you put the stock exhaust back on and your RPMs come back to something more reasonable givin that you are clutched for an SLP pipe setup (one that works...) I would not expect that much difference with the clutching but.... I for sure would be spending a lot more time looking at what you did between pulling the old pipe off and putting the new one on before I started tearing into the rest of the sled.

Only thing you changed from one ride to the next was the pipe - focus your attention there - best place to start. Good luck.

icr · Jan 12, 2016

die hard poo said:
This has a cable operated system, but I plan on taking the valves apart to inspect.

Right, I knew that :face-icon-small-con

Have you replaced the exhaust sensor in any of the pipe swaps?

die hard poo · Jan 12, 2016

No exhaust sensor replacement.

And I too thought to look at what changed(SLP pipe replacement), but after throwing on the stock exhaust and clutching it back to stock, its still low on Rpm, albeit I haven't ran it on the snow, just on the stand. I will try and drive somewhere with snow and test it to verify.

icr · Jan 12, 2016

Might be worth borrowing a sensor to take with you

trussell456 · Jan 12, 2016

running the sled on a stand to check rpm is useless. without load the sled will not pull the correct rpm. try the sled with the stock pipe on snow and see where your rpms are at

AKFULLTHROTTLE · Jan 12, 2016

I agree with the EGT sensor, give it a try for sure.

What oil are you running?

Both cylinders are 130+ on mine. WOT

AKFULLTHROTTLE · Jan 12, 2016

other the primary spring does the rest seam good? Rollers?

dboivin · Jan 12, 2016

i'm willing to bet your going to end up at resetting your base TPS voltage. if your pv cables are broke you would probably throw a code.

did you notice a massive change in tone of the motor when this started happening?

goto hardcore and look for "fade" threads. read for days. seek out posts by johnny cash on there.

having a dealer who knows how to how to check base voltages without digital wrench seems to be key.

sledheadd · Jan 12, 2016

AKFULLTHROTTLE said:
I agree with the EGT sensor, give it a try for sure.

What oil are you running?

Both cylinders are 130+ on mine. WOT

I'm thinking if it was the egt it should throw a code,

AKFULLTHROTTLE · Jan 12, 2016

sledheadd said:
I'm thinking if it was the egt it should throw a code,

For the 3 I have had go bad since 2011, none have thrown a code. Well I think they did leave a code in the ECU but did not throw a light.

IQRIDR · Jan 12, 2016

Axys 800 compression here at the shop has been 130 psi...however at 850 miles my valves were GROSS. But I also threw codes for valve positions not reached.

die hard poo · Jan 12, 2016

There wasn't a RPM fade, this was a light switch like drop in RPM. A lot of it too lol
TPS was calibrated at 150 miles to spec.
I run Amsoil Interceptor oil since day one
Swapped EGT probe with my good running pro-no change
Checked primary rollers, they were in good shape
Cleaned the exhaust valves, they were a bit gunked up but nothing bad. Didn't notice them stuck or any apparent issues.
Verified the exhaust valve cable and actuator operated correctly. (watched it as I ran the throttle on the stand. Seemed to go to three distinct positions consistently)

Took for a test ride tonight with stock pipe/can/clutching and it was still low on rpm, (8000rpm). But the snow was basically ice so there was no load on the motor. Most likely going tomorrow to the mountains to test again, but I don't expect any better results.

trussell456 · Jan 13, 2016

die hard poo said:
There wasn't a RPM fade, this was a light switch like drop in RPM. A lot of it too lol
TPS was calibrated at 150 miles to spec.
I run Amsoil Interceptor oil since day one
Swapped EGT probe with my good running pro-no change
Checked primary rollers, they were in good shape
Cleaned the exhaust valves, they were a bit gunked up but nothing bad. Didn't notice them stuck or any apparent issues.
Verified the exhaust valve cable and actuator operated correctly. (watched it as I ran the throttle on the stand. Seemed to go to three distinct positions consistently)

Took for a test ride tonight with stock pipe/can/clutching and it was still low on rpm, (8000rpm). But the snow was basically ice so there was no load on the motor. Most likely going tomorrow to the mountains to test again, but I don't expect any better results.

so your test ride showed 1000 rpm over what you were getting with the new slp pipe, and you were on ice. with a cvt clutch resistance=rpm so im willing to bet once you get into some actual snow instead of on ice your rpm will be even higher than the 8000 you were seeing on the test ride.

jmaxdox · Jan 13, 2016

First of all I hope you find your answers with everybody's helpful info on here. The fact that your seeing issues at just over 500 miles and that you say it happens like a light switch brings some deja vue feelings of my 60th Anniversary Switchback from last year. "Which I traded in to a dealer which was fully aware of my issues"

Does the light switch come and go? In other words has your rpm just gone down and went away or does it go from good to bad with no typical reasoning's? When rpm's drop a definite noticeable sound in engine tone. I started nicknaming my sled the blatting Goat when she would act up. "Never ever threw a Code"

My old Switchback would run great 20-30 miles then turn into a turd for a while. Like a switch start ripping azz again and bring a smile to my face for a while. Then the switch would flick and ruin the mood. Temperatures outside wouldn't help bring any conclusion. Dealers would hit their Polaris checklist looking for the problems without any success. "TPS, Exhaust Valves, belt, etc..."

Like I said, listen to everybody else's opinions and hopefully somebody helps you find the cure. I hope you find it and I will keep an eye on this thread to see where you end up. If you end up not finding any answers from the help of your dealer and the help of helpful people on the forums feel free to PM me. I've found that talking of such problems on the forums will get you called a troll and people don't want to hear it.
In all truthfulness I've been a Polaris faithful person my whole life
and would never stir the pot to try to tarnish their name.

I don't think I have seen anybody offer this info yet? Try a new belt.

sledheader · Jan 13, 2016

jmaxdox said:
First of all I hope you find your answers with everybody's helpful info on here. The fact that your seeing issues at just over 500 miles and that you say it happens like a light switch brings some deja vue feelings of my 60th Anniversary Switchback from last year. "Which I traded in to a dealer which was fully aware of my issues"

Does the light switch come and go? In other words has your rpm just gone down and went away or does it go from good to bad with no typical reasoning's? When rpm's drop a definite noticeable sound in engine tone. I started nicknaming my sled the blatting Goat when she would act up. "Never ever threw a Code"

My old Switchback would run great 20-30 miles then turn into a turd for a while. Like a switch start ripping azz again and bring a smile to my face for a while. Then the switch would flick and ruin the mood. Temperatures outside wouldn't help bring any conclusion. Dealers would hit their Polaris checklist looking for the problems without any success. "TPS, Exhaust Valves, belt, etc..."

Like I said, listen to everybody else's opinions and hopefully somebody helps you find the cure. I hope you find it and I will keep an eye on this thread to see where you end up. If you end up not finding any answers from the help of your dealer and the help of helpful people on the forums feel free to PM me. I've found that talking of such problems on the forums will get you called a troll and people don't want to hear it.
In all truthfulness I've been a Polaris faithful person my whole life
and would never stir the pot to try to tarnish their name.

I don't think I have seen anybody offer this info yet? Try a new belt.

I followed the fade issues fairly close last year but I don't think this guy is having the issue. Seems like it's a pipe issue (for whatever reason). If you read his post, it was after he changed to a different SLP pipe that it started, and the "light switch" hasn't been turned back on since. I haven't heard any fade issues with the 2016 sleds yet

AXYS Down on 1500RPM

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