Hi guys, I just got a Polaris Cyclone, I decided I am going to put in a new piston and rings, and by the looks of things it will need bored over,,,,but on the top of the piston, at pretty much the very top of the piston(the end of the piston that faces the pull start and is closest to the pull start) there is a capital F, and at the bottom of the piston(the side edge closest to the clutch) it says 5W25. What does this mean, is that something to do with the factory, is that something that means it has been bord over??? Help Please! Here is a picture of the piston and where the writing is, BTW i went over the righting in the program paint so it is easier to see.
http://img.photobucket.com/albums/v6...955_custom.jpg <youll have to copy and paste it

 

all i know is that the F stands for forward, make sure that when u put the new piston in, you put the F toward the front of the motor, as for the 5W25, i'm not sure what thats about.