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Discussion Starter #1
hi I'm new to this forum. I'm hoping to get some help with 2010 850 knocking and spitting oil out of plug in top of stator cover. I had the pcv freeze 2 years ago so I replaced valve cover with updated cover, everything ok for 2 yrs. This fall I had oil in air filter so I removed the felt filter on pcv and no more problem there. Machine locked up on me after a long ride and would not restart as if the motor was locked up, then after being towed for a few miles I tried and it started and ran fine for about a month then the same thing happened, wouldn't start and had to be towed then got it to start but engine knocking and belt smoking. Sorry about the long post and I know there's some similar posts. I CANNOT FIND WHAT CAUSED THIS, HOW DO I REPAIR, AND HOW DO I PREVENT FROM HAPPENING AGAIN. Was this caused from that pos pcv. I have a video of engine running but couldn't get it to upload. Tried talking to Polaris but that was of no use. Thanks for any help
 

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Welcome to the forum
Been around cars and motorcycle most of my life.
You need to get to that motor and figure out whats going on. Obviously ,And stop driving it.
If it starts, and its Knocking you need to check the bottom end.
It does not sound like good news to me.
 

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On the surface, it doesn't sound good. A knock when it runs is generally bad news. But on the off chance that it isn't inside the motor. When you pull the clutch cover, check the primary clutch out. Had a buddy with a Scrambler 500 and a knocking noise when it ran. He was sure it was inside the engine. I pulled the clutch cover, the buttons on the primary were gone and had been for a while. The knocking noise was the spider in the clutch hammering on the outer sheave. Clutch was toast, but still cheaper than an engine rebuild.

With your descriptions, it may not be that easy. But after towing it frees up and ran fine so it could be that simple.

Keep us posted please!
 

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Check vent tube between engine and trans for oil, if any replace the rubber load dampener that connects engine to the trans, when pcv froze it may have pushed out of rear main seal, and it causes the "spike load dampener" to swell and pushed on crank shaft and wears the crank shaft and engine cases, but sounds like you will need to remove and repair the engine,
 

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Discussion Starter #5
I only ran it long enough to try and diagnose and get a short video. The knock is pretty loud and there's oil all over the stator cover and spitting out the plug in stator cover, I don't think there's supposed to be oil in there. I checked clutches and all looks good there still knocks without belt on, replaced belt and it did not change anything. If only Polaris would let you talk to a tech, they just tell me to take to dealer and I talked with dealer and they had no clue but I'm going to repair myself, just need as much info as possible
 

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When you had the belt off you would have been able to see if the spider was flopping around, or at least been able to move it and tell that way. You can confirm it if you take the clutch off and start the engine. But yeah, oil in with the stator is not good. Must be building up pressure in the crankcase and pushing it out there. The knock is still not good though. Sounds like you are gonna need to pull the engine and start taking it apart. If you don't already have one, get a repair manual...either a Polaris book, or aftermarket book. Complete instructions and the specs you need will be in it. If you have the skills to dive into it you can just follow the book and be in good shape. I did my first 325 engine that way. Still use that book now when I need to look something up.

Good luck with it!
 

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Discussion Starter #7
yep gonna have to pull motor. But how do I prevent this from happening again, do I just replace pcv periodically
 

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Well, in the old days, the PCV valve was part of a routine tune up on cars. That was back when they were vented into a vacuum port on the intake manifold. So yes, periodic change of the PCV won't hurt. But lets look at why the PCV system is causing this issue on a somewhat regular basis. Is the PCV getting plugged up with gunk, or freezing due to moisture and cold or what? As far as I know, the PCV system is not a common problem on the 850, or any other for that matter.

What is your compression like? Lots of hours/miles on the machine? Is there a baffle inside the engine that is missing. Something that is supposed to change the direction of the air going through the PCV and help the larger heavier stuff drop out. If the rings are shot that can cause excessive blow by which would explain the extra crap going through the PCV system. Father-in-Laws mower was so bad he kept a handful of extra air filters in the garage so he could change it when one got too oil soaked to let the machine run.

Some of the answers can help you know what to look for as you tear down the engine. Careful inspection of the parts may be able to give you a clue as to why you have a problem in the first place.

Good luck and please keep us updated!
 

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Discussion Starter #9
From what I've read the pcv on the 850 was a real problem 09-12 freezing and oil in air box both of which I have had issue with so there should be a lot of insight on this issue. When I do rebuild is there any other issues I need to address while in there. I only have 1600 miles on machine
 

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With only 1600 miles on it, you shouldn't have to worry about anything except the knock. But you want to inspect all the parts. Particular attention to the piston skirts and cylinder walls for scoring. Then the crankshaft journals. You could have scored a piston, and I would bet your knocking is from a bad rod bearing. That's usually the first thing to go if they get low on oil.
 

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Leaned something about the 850 engines today. Had to stop at the shop anyway so I asked about that particular engine. They apparently have a very high compression ratio. Where on my 500 or 325 machines 100-170 psi on a compression gauge is good, the 850 engine is almost 300 PSI. A 200 psi reading is on the low side.

Before taking it out, I would pull the plugs and try to get a compression test. Might tell you what else you need to do while you have it apart. Good news is that the rod and main bearings are replaceable like a car in two halves.

Bad news is that you probably blew a crankshaft seal on the stator side for it to be pushing oil out there. With the high compression, you will want to check your rings carefully. They could be worn enough that it's pressurizing the crankcase more than the PCV system can handle. Shouldn't be with only 1600 miles, but it is something to check for.
 

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Discussion Starter #12
thanks stave7119 I will check compression, but it's going to be awhile before I get to it. Oil is 3/4 but I feel its a bearing caused by seal blow out. I'm not sure what's going on with the pcv valve, it was blowing oil into air box until I removed felt filter upon recommendation on other forums, maybe this was a cause I'm not sure
 

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No way 300 psi normal for that engine. The gas would com bust without a spark. 300 psi getting into range of a diesel engine. Anyone have a service manual for the compression specs ?

Pull your oil filter and cut open.if lots of shiny stuff in there take a magnet to it and see if particles stick to magnet. If they don't its aluminum and chances are you have a piston issue. If the do stick steel could be coming from main bearings or rod bearings
 

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180-210 is the spec for an 850.
 

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Thanks for the clarification, I obviously misunderstood what the mechanic said. It is still higher for an 850, than the other engines. Just not as high as I thought he was talking about.
 

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No that range 175- 200 is pretty standard for a healthy motor
Knowing the compression when you first buy a bike, car, whatever. It is always a good thing to document.
usually a warm motor and throttle is wide open,
skip the warm motor part,
if its knocking it sounds like the lower end, which sucks on a motor with such low miles or hours
but who knows
please keep us updated.
Updated I just looked in my work shop manual " compression pressure 210-250"
 

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Discussion Starter #20
I'm still not sure how this happened but I am sure the pcv was the cause but I cannot find anything wrong with it. Hopefully someone will have some info on the pcv valve.
 
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