Polaris Dragon 800 piston movement and low compression

[Cmonster]

Hey all, new to the forum. I am working on an '08 Polaris Dragon 800, just rebuilt it with a new cylinder and pistons less than 200 miles ago. I took it apart this week to see why I have low compression, and it feels like the pistons are really loose in the cylinder. I haven't ever tried to move a piston like this before so I'm not sure if that is normal or not. Here is a link to a video of the movement and of the cylinder walls. Please help!

 

[Over budget]

Somethings wrong it’s hard to tell in the video but theme marks on the cylinder wall look like like seizure marks. New head gasket won’t do anything to bring the compression back. I would tear the rest of the way down and inspect it further I bet piston rings and pistons are toast.

 

[Cmonster]

Thanks Bframpto, I did a compression test with oil poured into the jug and compression came right up to where it should be so I figured at least rings. Just crazy to me that would happen after 150 miles of use. Gunna tear it down tomorrow and see whats up

 

[spoon]

What did you end up finding? Slop in those pistons is normal on those motors cold. Clearance at top of piston to cylinder is not important as clearance is measured at skirt at bottom of piston.