In the installation instructions for wiseco pistons it says that if the cylinder has an exhaust bridge “which a Polaris 650 cylinder has”, then the piston should contain lubrication holes in the skirt, 2 of .300” down from the bottom ring at .060 dia, and at .375” centre’s. Which they don’t.

The instructions then tell the process to drill them your self, correctly. Which is fine, and I can see why they would be of use, what I mean is, do I really need to drill them or will they be ok left undrilled?

It would be a shame to drill holes through nearly 200 quid’s worth of pistons if I don’t need to.

Sorry but I’ve never seen or heard of lubrication holes in piston skirts before, I’ve had a lot of bikes in bits over the years and they never had any, and they all run fine with out them, and the standard pistons dont have them.any thoughts on their use i.e. advantages and disadvantage.



simon. 12 without the (N)