Interesting
I've been following this (and many other threads), as I snowchecked a 2013 ProRMK 600 for my wife - first polaris sled in the house since the TXL. My take on the "defective" motor is this: I believe the internet blows things out of proportion, and that you likely don't have accurate statistics (people posting about a machine they don't even own).
There has been numerous threads about polaris 800 reliability, but there has also been numerous threads about ski-doo 800r and cat m1000 engines over the years. Half of the failures can be attributed to modifying these powerplants, and not correcting fuel and ignition mapping issues. Most of the engines built today are dangerously lean due to EPA regulations, and NO TWO engines are identical - this stuff is mass produced and assembled with parts being provided by more then one vendor in most cases. In the last 10 years we have seen substantially "cleaner" engines that are making considerably more power then thier predecessors. I think it's safe to say that the manufacturer's have done well (for the most part). Of course, as soon as these machines are modified (even just a can), we are quick to blame the manufacturer and demand warranty when the product fails. I am not defending the "big 4", but some failures can be attributed to operator use, poor pre delivery inspection, and improper break in procedure. I've been fortunate that I've never had an engine failure over the years, but I also replace rings every 1800 miles on my two-stokes without fail, and ensure they have sufficient lubrication. Oil is cheap, especially when comparing it to downtime without a sled. Would I be choked if my new sled broke in the first season? Likely. Do I go over the new machine prior to riding it? You bet your life I do - helicopter rides out of the backcountry are pricey. In the end it boils down to having a good dealer that will look after you in a bind, and go to bat for you with the manufacturer. But the best way to inform a manufacturer of a problem is by voting with your wallet - if they aren't selling sleds, they will address problems. I am not brand loyal in any way, shape, or form, and my purchases reflect this.