I have a 97 rmk xlt 600. I just put a slip on silencer on it, got all new needles and seats put in the carbuartor. took it out saturday and it dies about 2 miles into the ride. So i looked at the plugs, the left cylinder there was no gap in the plug. I took it to the polaris dealer and they looked at it quick. they said it is the crankshaft bearings gone bad. They said this is common with these. with kind of makes me mad cuz it only has 1300 miles on it, and i havent even put 100 on it. But they said it was the piston coming up and hitting the plug. I took the head off, and there was definatly something wrong with the piston, chips in the side of it. My question is, where is the best place to get new bearings for this, and gasket set, and new piston. I am really not wanting to spend too much on this, but want to do it right. And has anybody else had to do this to there polaris with this motor?? how difficult is it? thanks

XLT's are pretty well known for having crank issues. Stock sleds are normally ok, but the cranks aren't known for having much extra beef in them. Put pipes on and in most cases it is just a matter of time til it pops again. The good thing is so many were sold used parts are plentiful. Unfortunately, the older Fuji motor parts prices have begun to rise with the shift towards the Liberty series motors. You won't know for sure until you get in there as to how much damage has been done. The 97 and up were supposed to be more reliable than the previous versions, due to an additional oiler line to the PTO bearing. There is quite a bit of information out there on XLT's as a ton were sold.

ok thanks, so do you think the reason for this is when i out the slip on pipe on? I was told it wouldnt do much at all if i just got the muffler, not the whole system.

I doubt the can was the cause of it, more likely a bit of rust on a bearing from storage, or perhaps you got one of the worse cranks out there. Some guys got several thousand miles out of them with pipes and all, while others blew several cranks in a couple thosand miles. While a good motor, the XLT was a bit underbuilt and didn't have enough reserve strength to take some of the loads they ended up seeing. There was a bigger PTO bearing kit people were using with some success. Generally if the thing was well maintained it was a bit of a crapshoot on whether you got one that lasted a long time or only lasted a short while. I suspect you may have simply got one that decided this was its time to let go, or perhaps it got some rust on a bearing while sitting and it finally let go. It is much easier to determine what went wrong with the engine disassembled than over the internet. Some people who liked the sled but became frustrated with the engine have taken to swapping in Liberty twins, or Ultra/XCR case reed triples, as these offer better performance and superior reliability. They require some work, but offer better performance and reliability.