[dremmick]

I have a 1999 mxz 600. Last winter my sled had significant compression loss. I think on the mag side its like 20 and the other side its like 90psi. Before the compression loss it was real quick up to 75 miles per hour then it wouldnt go any faster(at least thats what my speedometer said). Also on one of the pistons it looks like the rings are stuck(got burned into the pistons). In other words the rings wont rotate. I just want to figure what caused this problem before i rebuild it. Aslo how can you clean you flush your lower end with out removing it from the sled.

 

[tecateboy]

i would bet that you halfway cold seized the motor up....if you dont let your sled warm up for a couple minutes before you ride it, and then for the first few miles take it easy to let it warm up a bit more, it can cold seize, which is sorta what it sounds like, either that or you would get a 4 point seize from not letting it warm up where the piston seizes in the cylinder on the 4 corners of the piston.