2003 Polaris ATV Trail Boss 330 Factory Service Manual, Page 50Get this manual
PISTON IDENTIFICATION
The piston may have an identification mark or the piston may not have an identification mark for piston placementIf the piston has an identification mark, follow the directions for piston placement belowIf the piston does not have an identification mark, the direction for placement of the piston does not matterNote the directional and identification marks when viewing the pistons from the topThe letter "F",! ","" ormust always be toward the flywheel side of the engineThe other numbers are used for identification as to diameter, length and designFour stroke engine rings are rectangular profileThe numbers or letters on all rings (except oil control rings) must be positioned upwardSee text for oil control ring upper rail installationUse the information below to identify pistons and ringsEngine Model NoES32PFE Oversize Available (mm) .25 .50 Standard Piston Identification None
The following components removal for service: Camshaft Connecting Rod Crankshaft
require