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Discussion Starter #1 (Edited)
So, here is my problem.

I had to get a new frame for my 2013 850XP HO EPS. This was done at 82 miles, so unfortunately I did not get much seat time to know if I had a problem before frame replacement. I currently have about 180 miles on it.

The bike sometimes idles nice and smooth, and somteimes the idle will fluctuate, not to the point of making it hard to shift or anything, just enough that it has a lope. maybe erratic is a better term...

I have also noticed when the idle fluctuates, if I stab the throttle very quickly it will stumble for a split second before it picks up and revs up. I mean a split second, no long delay, it is almost hard to notice. I don't notice this everytime, just a couple of times.

I can pretty consistently shut the engine off and fire it right back up and the idle is fine again. I havent noticed any codes, but I don't know how to check them or where they show up on the display.

One more note, the best I can tell it is a little bit more prone to do this if I let it idle for a minute or two. It also happens sometimes as soon as I crank the engine.

It has never stalled, just annyoing, and I don't know what it could be, or if it is something major.

Any help or tips would be very helpful.

-Tim
 

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And codes showing up?
 

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I'd wager that the throttle cable is adjusted too tight. It should have a little slack in it.

THe sole authority of idle speed is the computer- acting through the idle stepper motor and a few sensors.
 

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Discussion Starter #4
And codes showing up?
No codes showing up that I have seen.

I'd wager that the throttle cable is adjusted too tight. It should have a little slack in it.

THe sole authority of idle speed is the computer- acting through the idle stepper motor and a few sensors.
curtwpk, thanks for the reply...I will go check the play here in a few minutes...I will let you know what I find with the cable tension.

I am assuming that you mean just see if there is some slack in the actual thumb throttle lever?
 

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Yes. There is a cable adjustment built into the cable about 10 inches from the thumb lever. It should be adjusted so there is a little slack in the thumb lever.

YOu must never use the cable adjustment to tighten the cable and increase idle speed. It goes totally haywire if you do.
 

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Discussion Starter #6 (Edited)
There is a pretty good bit of play in the thumb lever. probably just over 3/16" play from pulling the lever as far out as it will go, to when you feel the throttle cable move. Does this sound right?

One more thing, it seems like it may be a little bit more common when the machine is hot.

Another baffling part of this, is that it is intermittent.
 

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Change your plugs? I haven't had an issue like this, or with starting. But some people say their 850's fouled their first set of plugs pretty quick.
 

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Discussion Starter #8
Change your plugs? I haven't had an issue like this, or with starting. But some people say their 850's fouled their first set of plugs pretty quick.
Will do, is there a plug that most folks recommend over the OE?
 

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You can use the champions that are #8 the stock ones run a bit cold and are number 6s or a lot of us are using the NGK Iridium the number is

NGK for 850XP
Standard plug: stock 6799; part # LZKAR7A
Iridium plug: stock 6043; part # ILZKAR7A10
 

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Discussion Starter #10
You can use the champions that are #8 the stock ones run a bit cold and are number 6s or a lot of us are using the NGK Iridium the number is

NGK for 850XP
Standard plug: stock 6799; part # LZKAR7A
Iridium plug: stock 6043; part # ILZKAR7A10
Thanks for the info, I have run NGK iridium I'm my rubicon...which would you recommend?
I know the iridiums are prolly expensive, but if they are worth it I'll buy them.

Also how big of a hassle is it to change the plugs on the 850?
 

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The champion 8's are okay but I am running the iridium's. I like them and have had no issues with carbon fouling since I put them in.

These bikes need to also be warmed up and used as well. They don't do well being started, moved 10 feet and parked repeatedly.
 

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Discussion Starter #12
The champion 8's are okay but I am running the iridium's. I like them and have had no issues with carbon fouling since I put them in.

These bikes need to also be warmed up and used as well. They don't do well being started, moved 10 feet and parked repeatedly.
Thanks, I will go with the iridium based on your experiences. That could be the problem, as soon as I got it back I used it on my hunting property, moving deer stands putting out mineral blocks, etc... This means a lot of start and stop.

Hopefully the iridium plugs won't foul as easily when doing stop and go stuff.

Again, how big of a job is it to change the plugs? I know the job itself isn't bad, but how much crap do I have to take off to get to them?
 

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Not a big deal at all. Remove the seat, take the right side plastic panel off with 2 or 3 push pins and one torx 25 screw. The pliers in the tool kit are made to pull the push pins out.

Pull off plug wires carefully and remove plugs. Grease boots with dielectric grease and reinstall new plugs.
 

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Discussion Starter #14
Not a big deal at all. Remove the seat, take the right side plastic panel off with 2 or 3 push pins and one torx 25 screw. The pliers in the tool kit are made to pull the push pins out.

Pull off plug wires carefully and remove plugs. Grease boots with dielectric grease and reinstall new plugs.
Awesome, I will be ordering 4 of them immediately, that way I will have spares!

Thanks for the help!
 

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Not a big deal at all. Remove the seat, take the right side plastic panel off with 2 or 3 push pins and one torx 25 screw. The pliers in the tool kit are made to pull the push pins out.

Pull off plug wires carefully and remove plugs. Grease boots with dielectric grease and reinstall new plugs.
Awesome, I will be ordering 4 of them immediately, that way I will have spares!

Thanks for the help!
When you say it idles erratically does it sound like it is down a cylinder? I had a plug foul just a few miles after bringing it home from the dealership but has been great since. I think they get fouled when the dealers are moving them in and their yards and never warmed up.
 

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I would also say... before removing your plugs, always blow compressed air in the plugs holes to get any dirt out, so it will not fall right into the engine when you remove the plugs
 

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Discussion Starter #17
Not a big deal at all. Remove the seat, take the right side plastic panel off with 2 or 3 push pins and one torx 25 screw. The pliers in the tool kit are made to pull the push pins out.

Pull off plug wires carefully and remove plugs. Grease boots with dielectric grease and reinstall new plugs.
Awesome, I will be ordering 4 of them immediately, that way I will have spares!

Thanks for the help!
When you say it idles erratically does it sound like it is down a cylinder? I had a plug foul just a few miles after bringing it home from the dealership but has been great since. I think they get fouled when the dealers are moving them in and their yards and never warmed up.
Maybe kind of similar to miss on one cylinder, but not a dead miss, meaning like maybe a weaker than normal spark at idle sometimes!

I would also say... before removing your plugs, always blow compressed air in the plugs holes to get any dirt out, so it will not fall right into the engine when you remove the plugs
Will do, thx!
 

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I am having the same problem and I was wondering if changing your spark plugs fixed it?
 

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Same here.... 2013 850 xp LE, exactly the same problem you describe in the initial post - intermittent erratic idle, no error codes, no engine light, minor throttle delay. Only diff is mine will occasionally die when idling like this.

It started after I accidentally flipped the quad. I had oil in my air box after the crash so I cleaned it out and replaced the stock filter with a uni filter. My dealer said uni specifies the NU-8518ST for my model and year, but he recommended the NU-8503ST instead since it looks a lot closer to the stock filter. It barely fits in the air box and when I took it out to clean it after about 3 rides (one of which was very dusty), I was surprised to see that it didn't look dirty at all minus a small section near the open end. Not sure if I have the right air filter at this point, but one thing is that with the stock filter the front of my seat would always get unbearably hot whereas the seat is much cooler with this uni filter. Dunno if that's relevant though.

Anyhow, the idle problem was still there with the new filter so I replaced the stock plugs with the iridium model everyone recommends on here. My stock plugs were filthy and completely black so I thought for sure this was the fix. Nope - first time I started it up there was the idle issue, and it seems to happen even more often now.

One additional thing is that when I flipped the beast backwards it was just cosmetic damage but I remember the throttle body had slid a little on the handlebars and I just moved it back to where I thought it was before. I've been looking into that and came upon this thread but I'm a bit overwhelmed with all the possible issues - TPM and IAC and throttle cable adjustments and warnings to not screw it up, etc.. I'm not very experienced with working on engines at all, but I'm having fun learning. Are there any guides or maybe a service manual that gives somewhat basic instructions on how to make these adjustments and test them properly without breaking anything?

I'd like to try everything I can before taking it to my dealer as they are very...difficult to work with and are known to rip people off around here. Any help would be greatly appreciated.
 

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Same here.... 2013 850 xp LE, exactly the same problem you describe in the initial post - intermittent erratic idle, no error codes, no engine light, minor throttle delay. Only diff is mine will occasionally die when idling like this.

It started after I accidentally flipped the quad. I had oil in my air box after the crash so I cleaned it out and replaced the stock filter with a uni filter. My dealer said uni specifies the NU-8518ST for my model and year, but he recommended the NU-8503ST instead since it looks a lot closer to the stock filter. It barely fits in the air box and when I took it out to clean it after about 3 rides (one of which was very dusty), I was surprised to see that it didn't look dirty at all minus a small section near the open end. Not sure if I have the right air filter at this point, but one thing is that with the stock filter the front of my seat would always get unbearably hot whereas the seat is much cooler with this uni filter. Dunno if that's relevant though.

Anyhow, the idle problem was still there with the new filter so I replaced the stock plugs with the iridium model everyone recommends on here. My stock plugs were filthy and completely black so I thought for sure this was the fix. Nope - first time I started it up there was the idle issue, and it seems to happen even more often now.

One additional thing is that when I flipped the beast backwards it was just cosmetic damage but I remember the throttle body had slid a little on the handlebars and I just moved it back to where I thought it was before. I've been looking into that and came upon this thread but I'm a bit overwhelmed with all the possible issues - TPM and IAC and throttle cable adjustments and warnings to not screw it up, etc.. I'm not very experienced with working on engines at all, but I'm having fun learning. Are there any guides or maybe a service manual that gives somewhat basic instructions on how to make these adjustments and test them properly without breaking anything?

I'd like to try everything I can before taking it to my dealer as they are very...difficult to work with and are known to rip people off around here. Any help would be greatly appreciated.
If you look at my subscriptions I have a thread that has a couple other things to check. Also, which dealer do you go to? I live in CA too and was curious.
 
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