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cutting out/breaking up @ 6800-7k?! Just completely serviced!

S
Oct 27, 2017
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Hello all, i didnt want to have to post, but i cant figure it out and dont want to continue replacing stuff on a whim. I did some searching and cant fine anything with the same issues, or anything current, mostly stuff from when the sleds were new with a few hundred miles.
So... I just had my 2011 pro 800 out for the first this season. I just did a bunch of work to it, including plugs, reeds, cleaned exhaust valves, new fuel (91 w/eth), serviced the drive clutch, new belt, and more that i dont think would be applicable. Aesthetic and suspension stuff.

Of course, on the trail up, my snow flap got stuck up under the tunnel and i did not notice until my sled started to bog out from overheating. It got quite hot, i did not notice because my gauge pod was relocated down next to the gas filler, and it was stuck in Celsius and i wasnt sure what the temp was. Come to fine out it was quite hot, 110c aka 230F! I know, no good, but got it cooled down and turned around to go grab a different sled and on the trail down i went to wack the throttle a couple times and it was breaking up. Got it home and just replaced the plugs again and put some seafoam in it. Ran it a bit and same thing. Runs fine, actually better at idle. It was not wanting to stay running at idle and now it is, could be a coincidence. Seems to run fine up to that, i can give it some throttle and it pulls fine, power seems fine, its just when i give it wot it breaks up. Suggestions? ideas?
 
Last edited:

RoostinRyan

Well-known member
Lifetime Membership
Dec 27, 2013
301
59
28
37
Yakima, WA
Hello all, i didnt want to have to post, but i cant figure it out and dont want to continue replacing stuff on a whim. I did some searching and cant fine anything with the same issues, or anything current, mostly stuff from when the sleds were new with a few hundred miles.
So... I just had my 2011 pro 800 out for the first this season. I just did a bunch of work to it, including plugs, reeds, cleaned exhaust valves, new fuel (91 w/eth), serviced the drive clutch, new belt, and more that i dont think would be applicable. Aesthetic and suspension stuff.

Of course, on the trail up, my snow flap got stuck up under the tunnel and i did not notice until my sled started to bog out from overheating. It got quite hot, i did not notice because my gauge pod was relocated down next to the gas filler, and it was stuck in Celsius and i wasnt sure what the temp was. Come to fine out it was quite hot, 110c aka 230F! I know, no good, but got it cooled down and turned around to go grab a different sled and on the trail down i went to wack the throttle a couple times and it was breaking up. Got it home and just replaced the plugs again and put some seafoam in it. Ran it a bit and same thing. Runs fine, actually better at idle. It was not wanting to stay running at idle and now it is, could be a coincidence. Seems to run fine up to that, i can give it some throttle and it pulls fine, power seems fine, its just when i give it wot it breaks up. Suggestions? ideas?
I had a similar thing happen and it was the throttle safety switch. When I wouldn't press the throttle just right, usually while standing, it would cut out. I ended up eliminating it and haven't had any issues with cutting out when I hit the throttle wide open.

Sent from my SM-N950U using Tapatalk
 
S
Oct 27, 2017
20
1
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I had a similar thing happen and it was the throttle safety switch. When I wouldn't press the throttle just right, usually while standing, it would cut out. I ended up eliminating it and haven't had any issues with cutting out when I hit the throttle wide open.

Sent from my SM-N950U using Tapatalk

I forgot about this, I also installed a munster finger throttle, and had to bypass the TSS using their supplied resister. Ill have to contact them and see if they ever have issues like this. How did you bypass it ryanlinger?
 

RoostinRyan

Well-known member
Lifetime Membership
Dec 27, 2013
301
59
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37
Yakima, WA
I forgot about this, I also installed a munster finger throttle, and had to bypass the TSS using their supplied resister. Ill have to contact them and see if they ever have issues like this. How did you bypass it ryanlinger?
I took it apart and spread the contacts apart so they were no longer touching.

Sent from my SM-N950U using Tapatalk
 
S
Oct 27, 2017
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Just tested the resistor and it seems to be where it needs to be, 67.9k. Let her warm up and it is actually cutting out/breaking up/missing as low as around 4k rpm. Hard to tell as i dont want to hold the throttle while its up in the air, as well as not pissing my neighbors off to much. I got a couple videos of it, ill upload to youtube and post links here
 

RoostinRyan

Well-known member
Lifetime Membership
Dec 27, 2013
301
59
28
37
Yakima, WA
Im a little surprised that worked for you, from what i know theyre pretty sensitive to resistance.
It's still running through one resistor but not the second one. I'm not sure if it's different but mine is a standard rmk with the different controls so I'm not sure if it's the same exactly. If definitely works though. I'll watch the videos at my lunch break.

Sent from my SM-N950U using Tapatalk
 
S
Oct 27, 2017
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I just cleaned the spark plug caps as well. The dielectric grease i put in them just yesterday was black in one and getting there on the other. Seems a little better but still wont pull past 7k rpm. This is with the track suspended in the air. doesnt seem to be running quite right at idle either but i may just be hearing things. Im seeing things from injectors to reeds to coils and everything inbetween! So frustrating!
 
J

jim

Well-known member
Nov 26, 2007
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Boise
Lots of smoke...looks very rich. I'd check powervalves and/or injector issue. Also check oiler...I believe they stick to wide open if disconnected or any issues there. All I know, is it is smoking a ton and sounds very rich...powervalves that don't open or too much oil or gas make it sound that way.
 

RoostinRyan

Well-known member
Lifetime Membership
Dec 27, 2013
301
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Yakima, WA
Sounds like it is dropping a cylinder and hitting a wall to me. Hard to tell from the video. You probably already did but check your wires insulation? Mine always seem to wear a spot through one of them. What's it running for compression?

Sent from my SM-N950U using Tapatalk
 
S
Oct 27, 2017
20
1
3
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Sounds like it is dropping a cylinder and hitting a wall to me. Hard to tell from the video. You probably already did but check your wires insulation? Mine always seem to wear a spot through one of them. What's it running for compression?

Sent from my SM-N950U using Tapatalk

Wires look fine. Just did a compression test and its 110 psi on both cylinders. Fuel pressure is 57-60 psi.
 

Murph

Polaris Moderator/ Polaris Ambassador/ Klim Amb.
Staff member
Lifetime Membership
6800-7000 rpm

This is around where the powervalves should open. Have you cleaned them, checked bellows for rips or tears, cleaned small VES ports in cylinders? Checked VES solenoid operation.

Also, what about fuel filter? When was the last time it was changed? They typically only last about 1000 miles (less with race gas)
 
S
Oct 27, 2017
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6800-7000 rpm

This is around where the powervalves should open. Have you cleaned them, checked bellows for rips or tears, cleaned small VES ports in cylinders? Checked VES solenoid operation.

Also, what about fuel filter? When was the last time it was changed? They typically only last about 1000 miles (less with race gas)

Yes i just cleaned them as part of my preseason service. Bellows looked fine, and i did clean the ports in the heads. I may have to check over it again. No idea on the fuel filter, i bought the sled last year. Im going to order one and change it so i know its good. It seems to be running rough before 6800 though. I have not checked the solenoid operation though.
 
S
Oct 27, 2017
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Had a similar problem last year always around same rpm. turned out to be throttle position sensor. There is some great info here in SW on the TPS. Good luck.

bigM Was the sensor it’s self bad or was it just out of adjustment? It’s running rough all over and won’t rev past 7k. Running really rich as well.
 
S
Oct 27, 2017
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Well, I went to check and adjust the tps. One small problem though.. the ecu won’t power up via an external power source. When I supply it with power the fuel pump buzzes for a second and thasbit. No gauge function at all. Thought maybe it was the wiring so ended up tracking down the pins on the ecu and powering up there and same thing. Nothing. I know I have powered up the sled with a battery recently but can’t for the life of me remember if it was before or after I took it up for the first ride. Not sure if this ecu issue is the root cause of the poor running or just another issue..
 
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