Hi all, my first post here on SnoWest forums and i just want to thank everyone in advance for your help and pointers. I bought a 2018 Switchback 800 this winter after a long hiatus from riding and things have changed a bit since my last sled. Ive already put 1700 miles on this winter with roughly 600 of them put on this last week in the Black Hills where my issues began. I was told by the dealer that i bought this sled from that i wouldnt need to do any clutching changes from where i ride here in North IOwa to the Black Hills which i found a bit odd but went with it anyways. My sled ran fantastic the day we loaded it up in the trailer to head out and when we got there the thing ran like **** from the start. The first day i couldnt get it to rev past 7700 and as the day went on it got worse and worse so i went to the Polaris dealer in Rapid CIty and got 62 gr. clutch weights and swapped them out with the 66's that were in there. Nothing changed, same problem as before but as the day of riding went on i couldnt get the water temp to run past 94. So now im thinking that my thermostat is stuck wide open and knowing that the engine wont run well without it being around 110 to 125 ish along with good pipe temps im thinking that this couldnt be the issue. So i called the Polaris dealer in Rapid City and they didnt have a thermostat on hand and wouldnt be able to get one in a reasonable time so i went ahead and choked the water flow off a bit with a hand towel wrapped around the heat exchanger hose and a vice grips and got it to run consistently at 115 to 125. I was finally able to pull 8000 rpm the next day and thought that i had the problem solved only to have the rpms fade away as the day went on. I just got back yesterday and have been reading threads on the exhaust valves and relay issues so ive went ahead and cleaned that all up, rode it and no difference. Last night i decided to pull the exhaust valves and see what they looked like and holy crap for a mess. I just cant see how these were not atleast part of the issue if not the issue as dirty as they were. Im planning on riding it today to see if this fixes things but i wanted to see if anyone else has had similar issues and could maybe steer me the right direction on things. I still have not done anything with the thermostat as of yet but plan on replacing it today if they have one. The other question i had was if i was to put a 137x15 with 2" lugs on it how would that do in deep snow in comparison to a 144" or even a 153"? I would love to get something i could ride out west but with that kind of setup i wouldnt get much use out of it here at home. Again thanks in advance for your pointers and help, i really appreciate it.