2008 Polaris Sportsman 500 EFI/X2/Touring/500 H.O. Service Manual, Page 104Get this manual
ENGINE Piston Installation
12Clean the gasket surfaces on the cylinder and crankcaseRemove all traces of old gasket materialMake sure the cylinder mounting bolt holes are clean and free of debrisTang Outward
Cylinder Installation
78Place the dowel pins in the crankcase and install new cylinder base gasketPosition the Piston Support Block (PN 2870390) (A) beneath the piston skirt to support the piston during cylinder installationA
Install new circlip on one side of the piston with the end gap facing up or down, and tang outwardApply clean engine oil to ring compressor and install the compressor following manufacturers instructions