So last week I took the 850 to the shop because of a hard start problem and a major lack of power. It was diagnosed as engine worn. Only 110 lbs and 150 lbs of compression. This will be the second engine problem on this 2012 quad. The oil and filter has been changed every 50 to 60 hours with a new air filter and sock each time. After this I don't have a lot of faith in the Mexican built North Star engine. The first engine made it 800 miles when a rock dislodged the oil filter resulting in a total engine failure, block and all. That was not a polaris quality problem. The current engine now has right at 5500 miles and about 300 hours. I think this is poor quality.
850 engine failure
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you sure you didnt suck in some water, or dirt? 300 hours seems a bit early to be losing compression. do you have an extended warranty?
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I know this probably doesn't matter but I'm definitely curious as to which oil you were using?
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7,074 Posts
If you haven't torn it down yet, check the timing first, and then check the valves and piston tops for damage when you open it up. Had the exact same symptoms with mine when the timing chain tensioner broke in it. Timing was all over the place and pistons were hitting the valves. Compression was way low and it was very hard to start and wouldn't stay running until completely warmed up. Guess I'm saying that a worn engine might not be quite accurate. It does require a complete rebuild though if this is what happened to yours. Not just honing and replacing a few parts. Everything from the crank to the valves. If it is warrantied, don't let them cut any corners. They had to rebuild mine twice because the first time around they didn't replace the crank. The gear is pressed on the crank so you can't replace the gear without replacing the crank. They also didn't replace the timing chain. DUH... The whole failure was timing related, so why wouldn't you replace everything that is related to the problem??? Anyway, 1,000 miles later and all is good.
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What is your riding style and terrain type? (After reading rock / oil filter statement)
What oil / filter.... also curious?
Was it broke in propperly?
Machines fail.... it's a simple fact! You just happened to be the "lucky one".
But, I'd agree 300 hours seams young, but 5500 miles is almost a lifetime worth miles for me.... really depends on how it was used and/or abused and how well it was maintained. But still.... machines can fail.
I'd have to think the comment of hone the cylinders and slap in some new rings would solve the problem..... at least good enough to sell it, if you lack confidence!
What oil / filter.... also curious?
Was it broke in propperly?
Machines fail.... it's a simple fact! You just happened to be the "lucky one".
But, I'd agree 300 hours seams young, but 5500 miles is almost a lifetime worth miles for me.... really depends on how it was used and/or abused and how well it was maintained. But still.... machines can fail.
I'd have to think the comment of hone the cylinders and slap in some new rings would solve the problem..... at least good enough to sell it, if you lack confidence!
I have the extended warranty so I am hoping that it will be covered. I have always used Mobil 1 0-40 and Fram filters. The air filters and socks are always Pure Polaris. It is mostly in Az so it has not seen any water or mud. My riding partner and I always try to stay back out of each others dust. The first engine was a complete long block and only the things like water pump, fuel injection, charging system etc was reused. The old block was trashed the bearings seized when it lost the oil so it was all changed out. I will keep you all posted on progress. This is really discouraging as the machine has had nothing but one problem after another. The first engine was just one of those things that happen but everything else is a bit much.
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With that being said when it comes to an atv or auto I would just "Remove engine and replace with new one" A thousand miles later all is good? With the pistons slapping the valves? If its that messed up why would you want it fixed , or even want to fix it?. Much cheaper to just replace it
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Guess you didn't read the part about it being rebuilt a second time. And no, it isn't cheaper to just replace it, not to mention that's not up to you when it is being repaired under warranty. Other than the block and the head, it is pretty much a brand new engine anyway. As I said, everything from the crank to the head was replaced the second time around.
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Wow! No joke. 6500? The same bike without power steering in my neck of the woods can be bought for around 8500 if not less. What a rip off. Hope it turns out ok in the end budNo new word from the dealer today. I do know what it costs to replace the entire long block. $6500. I could do a total rebuild on my Cummins for that.uch:
Not to start an oil war but this statement doesn't make sense, best synthetic oil and the cheapest crappy filter?
The 1st failure wasn't Polaris fault, the engine should go 3000 hrs. or so. Was it replaced with a new engine? or just rebuilt. If rebuilt its only as good as rebuilder.
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Oh dear god, not the fram war. I see this battle go on, in every forum that I am on. I used to run fram exclusively on everything I owned and had absolutely no issues with it. The only reason I switched to Bosch now, is because Wal Mart stopped carrying fram.
Bottom line, a filter is a filter. If you don't try to run it for 10,000 miles you won't have an issue. Even more so on an atv with 50 hours on an oil change, with synthetic oil.
Bottom line, a filter is a filter. If you don't try to run it for 10,000 miles you won't have an issue. Even more so on an atv with 50 hours on an oil change, with synthetic oil.
May as well run the cheapest oil too. Oil is oil?
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245 Posts
I have to chime in here. Fram oil filters use cardboard as the filters bypass. If pressure or anything eles goes wrong, the cardboard pops and dirty oil goes back into motor unfiltered.
I ran Frams all my life also until a couple of years ago. My last vehicle I sold had over 250000 miles on it with a Fram filter from its first oil change until it's last. I still see that little Ford Ranger from time to time around town. Just has a few dents in it now but it is still rolling. I guess miles don't prove anything this day and age.
Ronnie
Ronnie
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3,230 Posts
Isn't that the point of the bypass?
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