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Hey guys I'm new to Polaris ATV's. I picked up a 2013 sportsman 550 for a good price even though it needed some TLC. It's got around 750 miles on it. I knew it smoked when I bought it and I've been trying to figure out the problem. First thing I did was a full service with Polaris fluids, air filter, spark plug, the works. It smokes at startup after it's been sitting a day or 2, goes away after 5 minutes or so. Also smokes if you're just cruising then gas on it hard. Compression showed 150 dry and wet, manual says 70-90 I believe. I've changed the valve seals since that can cause smoking but it still seems to be doing the same thing. Is the 150 compression ok or could I still be needing rings ? Rings cause constant smoke I thought ? Any help appreciated guys
 

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I was going to say valve seals but since you have changed them im thinking oil ring on the piston.
 

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If the PO did not change the oil regularly, the oil ring may be nearly worn out - a worn oil ring will let oil creep into the space between the compression rings and when cruising, oil will be consumed, but a slight and steady rate, but then when you open the throttle, the oil trapped between the rings will be drawn out rapidly and cause smoking. Also, even with new seals if the valve guides are worn excessively, the valve may 'rock' in the guide sufficiently to cause the seal to lose contact on one side of the stem and allow oil to be drawn through the guide.

If it smokes more the hotter it gets, but never fouls the spark plug, it's probably exhaust valve related.
If it smokes more upon cold start and decreases the hotter it gets, it's probably intake valve related.
If it smokes more the hotter it gets, and fouls plugs, it may be intake valve or ring related.
 
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